The i52500k would be better for gaming, but the FX-6100 should be fine.
However, the GT 430 is a very weak video card. You need a powerful video card with at least 2GB of VRAM to attempt to set everything on high and long draw distance in GTA 4. 4GB of VRAM on a GT 430 is simply a waste as the card is too slow to even make use of 1GB of VRAM.
None of the games you mentioned uses 4 cores, they all use 2 cores. Even though GTA 4 only uses 2 core, it seems to run better with a quad core CPU. It is a poorly ported console game.
The "best configurations for gaming" depends on how much you want to spend.