there are a couple of a sisterhood lists here and here no idea as to how balanced they are, I know Consul Avenging Angel personally and he's been doing good work with his list
if you go down the marines avenue then a battle company is a good starting point, you will want transport for the devs, and will almost certainly find assault marines to be quite bad at their intended role
to that I would suggest adding hunters, razorbacks, scouts, land speeders and eventually thunderhawks and terminators, the training scenarios in the rulebook are good to get to grips with the rules, then hopefully you can find a local player who can show you the ropes!
