Okie-Doke, budget build coming up, "Cheap as possible!" If all you're going to be doing is CS1.6 and FS:X as the most graphically intensive game, you can go pretty cheap on that, absolutely. Everything I post below is meant for pricematching at NCIX, not for buying from! Let's see...
CPU:
E5200 - $90
Mobo:
Foxconn G31MV-K - $52
RAM:
4gb (2X2GB) Corsair XMS2 DDR2-800 5-5-5-18$59 before $30 MIR
GFX:
Sapphire 4670 - $90 before $10 MIR
HDD:
WD Caviar SE16 320GB - $55
DVD:
Samsung SH-S223/BEBN blah - $23
Case and PSU:
Some cheapo Foxconn Case+PSU combo - $63
Pricematch all this at NCIX and it comes to $432 before taxes + shipping