Might want to check out Cliffed and/or ADD, I haven't played either, but they're g2b near future purchases, if iTunes ever decides to realize that my security code IS valid -_-
All you need is Rogue Planet. Just bought it and it is without a doubt the best TBS yet. Other than that it really doesn't matter as RP will take most of your time. IF you can though, try to get COD: Zombies.
I have none of those, but I've heard REALLY good things about Rogue Planet and Harbor Havoc. (I suggest Cliffed! It's a really addictive game.)