i got both games for around $3.75 each from steam (during sales). You can wait around for these, but I am not sure how far steam games can be modded. If you plan to mod, be on the safe-side and pick-up the CD
i prefer playing on my xbox 360 rather than my pc. Console gaming seems far more slow-paced and relaxed. IMO people take PC gaming far too seriously, which leads to a hugely comptetive environment.
So I just chill on the xbox 360
please - his cpu is fine for 4870x2 quad fire ~ and for $200 you get all the gpu power you will need until the next-gen consoles (not including Wii 2). Only cons are: no DX11 (not that dx11 is being used much in games), they run hot, loud, and draw quite some power.