The next installment i'll voice my opinions on for the codex marines book is the troops, and dedicated transports less the Land Raider as I'll cover it in the Heavy support section.
The marines n training. Due to their nerf on the BS and WS stat they've dropped a notch in my book, but still can find their uses in lists. One such choice is a squad with sniper rifles and camo cloaks sitting on a home objective offering cheap fire support as well as cheap scoring troop unit.
The next is as a surprise assault squad. Yes I kid you not this can work. 10 scouts, sgt with PF and combi melta, 5 scouts with BP/CCW and 4 scouts with shotguns. This works well dropping out of a land raider with maybe a chaplain or if possible khan attached.
With the furious charge of Khan the scouts are now hitting S5 T5 just like marines would, or if yu have the chaplain hitting rerollable I4... or if you get both have the combined benefits above, but are now a bit more expensive. The idea is you drop them out of the land raider as close as you can (So aim to be 1 inch from the direction you want to attack, remembering if possible to get your unit so almost all yours can attack and some fo the enemy if possible through pile in moves can't, though this will only work if the enemy is spread out in a line. open fire with the 5 shotguns (8shots) and BP's (5 shots) plus if you want the Sgt's melta or BP, (and whatever weapon your HQ has) then charge in.
Even without an Hq attached the unit will do well vs. most non deathstar units surprising a lot of people to how well scouts can possibly do in CC. Best use I’ve found it hitting an opposing troops choice or support unit like long fangs, dev squads etc and ruining them. The enemy now has to either open fire on your scouts and deal with them (which they likely will if you eat up one of their squads) meaning the rest of your force can dodge shots otherwise aimed at them and pile in some hurt. And remember with camo cloaks the unit if in cover will get a 3+ save, and if you don't have an HQ that alters combat tactics, you can go to ground lose a few men, choose to flee, and auto rally in your next go and move where you want and repeat.
The next type is a 5 man squad with camo cloaks, bolters and heavy bolter. Infiltrate them on a flank in a building and use them as a midfield support unit to add some fire while your marines in rhinos move up.
I've never bothered with locator beacons with normal scouts due to possibly dying quickly, but if you get them into a LOS blocking piece of terrain you can sue them as a cal down point for pods or even deep strikers or as a forward port location for a librarian and some thunder hammer termies. This cheapens the cost to get them across the table and also lets the scouts help in hand to hand on easier targets, meaning they can sweeping advance the ruined unit hopefully after the termies mess them up.
I’ve tended never to put a ML into the scout squads, while 1 Bs 3 missile may make the difference in a game every so often you're effectively wasting 9 shots from the others. Thus its best to give them a heavy bolter and Snipers if you want to take down MC's or bolters for hordes.
The backbone of marine armies, while other marine armies get better specalised troops these guys are still worth a look. The ability to take multi taking combos can be alluring such as Missile launcher and flamer but this makes the squad too multipurpose. I've found it’s sometimes easier to give them a duty and have them stick with it.
For example the tank hunters, multimelta, melta and combi melta on sgt with power fist or meltabombs. This units role is to take the midfield and support other units, or to sit back and act as a bunker between enemy vehicles and your objective. It works well with a Flamer, ML squad if they focus on the anti infantry and only use the ML for good side armour shots or as a backup single shot if no infantry present themselves.
While some people like to spec up the tactical squads with plasma guns/cannons, lascannons etc I’ve found them just too much of a liability or points sink. You can get anti tank elsewhere for cheaper in the codex; your tacticals are the solid anti infantry marine armies need.
For Sgts, its either one of 3 builds for me, the PF, combi weapon combo, The combi bolter, BP combo, or the untouched base bolter/bp. the tooled out one is good for the extra anti tank shot, the threat of instant deathing your enemy IC's or putting wounds on big gibblies. the combi guy is cheap, looses nothing but adds a single shot of whatever is needed (I'm mostly a combi melta guy, but having a flamer in the squad means taking a combi flamer and a ML makes a nice anti infantry squad). Finally the base Sgt is taken with the bolter as I find Tacticals do better boltering things than charging, and with a 3+ to always hit and anything from 3-4+ on normal enemies up to 5-6+ for the tougher enemies, you'll have better luck than 1 extra normal attack which needs 4's to usually hit and 4+ usually to wound unless you're fighting guard. DE, Eldar and the likes have higher Ini which means that single extra attack is even les useful than an extra bolter shell at 12 inches.
Support your tactical sand you'll find they prove to be workhorses for the army, don't expect them to be heroes and you'll get better results.
The faithful horse for the marines. It’s cheap, dependable, has 3 access points, 2 fire points, a storm bolter standard and all for 35points. They are very effective for moving troops, providing bunker fire or even for blocking enemy movement. My motto is ‘keep them cheap’. So they may get a dozer blade, but I’m not a fan of giving them anything more especially when their so cheap to begin with and purely for a protected get there and forget role.
Consider them in your army as roadblocks if needed. You should never feel bad about driving them forward right in front of units (usually 2 rhinos do this perfectly if free) and turn sideways and pop smoke. This means the enemy will have to spend movement going around the rhino allowing you another turn of firing. and if you use two rhinos feel free to make an arrowhead with a under inch gap between them... this means the squads in the arrowhead can fire through the gap but the enemy cannot assault through meaning an extra turn of firing, and if you moved the rhinos 12 inches and popped smoke they should live for you to tank shock the enemy unit (If there is no threat to the rhinos)into a nice flamer or blast marker formation. Or even to re-embark and flee the scene.
Some people I know like to add a Hunter-Killer purely for the surprise chance shot at side armour, and also to give it another weapon destroyed option before taking imob results... but that’s 10 points which could be used on dozer blades or combis. So think carefully before you bling up the rhino... it’s still a cheap date underneath all the extras and dies just as easily.
Not much can be said about the drop pod, its effectively a 1 trick pony... or is it. The most common use people have is dropping a dreadnought or sternguard squad (Or something similar) with meltas inside combat squadding on arrival and blowing up two tanks, or hopefully 1 with the dreadnought then relying on that unit soaking loads of fire next turn so the rest of your army can exploit the damage done to the enemy.
But I've also enjoyed using them as blockers and terrain makers for some of my armies. looking at your enemy's fire lanes, if you go first then drop them down to create some cover for advancing forces around the mid table, or if you need to, use them to land on objectives to keep the enemy from claiming them unless they waste firepower removing the pods.
Another somewhat reliable method is dropping the empty pods (Assuming you bought them for riflemen dreadnoughts who won't need them) is to pod in a land raider by dropping them around it to block its movement, hopefully making it unable to move or have to drive through terrain and it breaking itself. Although these pods can add up, but if you're playing a podding force it might be worth it to use a few for early game blocking while you take a part some of the enemy's movement.
The cheap gunboat of the codex marines army, loading these up with either twinlinked lascannons or lascannons/twinlinked plasma guns gets you more bang in the army for a cheap buck, but with AV11 they will die to most S7 plus weapons. The reason I prefer these weapon load outs are firstly the lascannons are welcome additions for shooting vehicles up or instant deathing annoying models. The TL-Plas/las adds another weapon system in so 1 weapon destroyed won't stop your destruction and with 3 shots killing most things without saves outright, it’s a nice thinner for marine squads or other similar units.
While assault cannon and heavy bolters might be suggested by some I dislike them in codex marine armies due to the slow speed of the vehicles. In blood angels assault cannons work better due to the fast rule, but in codex marines their low range hurts when you need to stun lock enemy formations. Its surprising how addig 1 more Str (GK codex) makes them into something really nice...
The heavy flamer mount is a horrible option in codex marines but blood angels can make it work nicely due to fast again.
The sucky point of razorbacks is that you can't fire out of them, but it’s a trade off to have some of the heaviest weapons in the game mounted to transport vehicles, and I personally rate them one of the best transports in the game for points to gun power ratio.