Xelloss on 16 November 2009
FPS, slightly older system... no brainer, Battlefield 2. Now only 30$ including the expansions and boosters etc.
RTS... Supreme Commander, and Sins of a Solar Empire. Supreme Commander can be picked up super cheap last i looked on Direct2Drive ( 20$ for game + expansion) , Sins should be cheap now to - definatly get the entrenchment micro addon, it adds lots of units and tech etc.