Wow, feel like I haven't helped anyone out with their lists for ages...
so for mobility what would you recommend?
Mobility means things that move faster than standard infantry. For most marine armies, this means Rhinos and/or Razorbacks, with Land Raiders for the Termies and Drop Pods for the Dreadnoughts.
Transports in general offer you several advantages over being on foot. As Hymirl mentioned, it gives your dudes more speed for them to cross the battle, allowing you to cross the table to reach other objectives and what have you quicker. A Rhino to cover 24" in two turns, it'll take an infantry squad around three, if you sacrifice your shooting to run. And probably more turns as you'll want to stick to cover. Another advantage is that it protects your dudes from fire, as your opponent will need to open your metal box before he can attack your weaker infantry inside. Marines are tough, but sat out in the open, there are plenty of weapons that'll ruin their day. Being in a transport (even if it's later destroyed) protects them from all that nasty fire.
i wanted them to be able to tackle any strong c c squad with ease
To be brutally honest, they'll fold as soon as something genuinely good in CC looks their way. Thinks like massed Genestealers, Hive Tyrants + Guard, kitted out Thunder Wolves and Nobz squads etc etc. If you want to make a truly combat monster out of them, you'll need to invest some
serious points into them. Not just put a PW on every guy.
Things I'd look at:
Being on bikes (added toughness and charge range)
Everyone taking a PW of some sort (Lightning Claws give you most bang for your buck according to mathammer)
At least two Storm Shields (preferably on guys you're not too bothered about loosing, so keep the upgrades on these ones low if you can)
A couple of Flamers/Melta/Plasma Guns, to soften up targets or open up enemy transports.
Definitely include a least one Power Fist/Thunder Hammer for tough targets/targets of opportunity.
You could also go for the wound allocation game. Use different equipment to make every model unique to abuse the system slightly.
And after all that, you'll still be left with a bloated squad of 5 dudes in Power Armour. Don't get me wrong, CC Command squads can ruin most armies, but for the points you pay, you could take a unit of Assault Termies (minus the Land Raider unfortunately), who'd do the same job for less points.
But, at the end of the day though, it's
your army. You take whatever the hell you want to
.
i wanted the powerfist as an insurance policy just so if something big comes to visit them they could have a chance, and i like the special ammo on the heavy bolter but i do have a missile launcher if it would be better
Forget it. If something gets in combat with your Scouts that you need a Power Fist to fight it off, the squad's as good as dead anyway. I'd suggest dropping the Power Fist and use the points for more Scouts (and give them all Sniper Rifles to make a decent shooting squad out of them). Or go for a CC based squad, in which case I'd try to find the points for a Land Speeder Storm, and give the Scouts Bolt Pistols and CCWs.
i was thinking of getting 1 or 2 more bikes and maybe dropping the assault squad and putting the vanguard on jump packs to use the heroic intervention
Heroic Intervention is cool, but like the Command squad, you'll need to invest a lot of points to make them work. I've tried them repeatedly against a variety of opponents and they always seemed rather "meh". Reserves screws them sometimes and others, they just don't seem to have the punch your paying all those points for. Not to mention building an army list to work around them (I tried for massed Drop Pods with Locator Beacons). Vanguard are good in a Blood Angels army, thanks to their fancy Jump Pack rules, but for regular marines, Assault Marines provide a fairly good JP unit, especially when paired with a Chaplain (which, by the way, wouldn't work with the Vanguard).
Hope this helps man
.
Thanks