I am a bit out of touch with all the new graphics cards.

Current System:
Abit BX6r2 MB
Celeron II 633 / 66mhz (New haven't tried to overclock it yet)
512 MB PC133 SDRam
40G WD HDD
Creative Graphics Blaster Riva TNT 16MB
SBLive +MP3
Plextor CD/RW 12/10/32A

According to Abit the BX6r2 MB supports 1x and 2x AGP. But they haven't answered as to whether it can support 4x. And I have no idea if the 4x boards are backwards compatible.

Basically I am asking: What Graphics card would be supported and still be higher up on the food chain than the one I have.

Any suggestions would be appreciated