You should try an old Abit BE6 v II b/c it gives you incremental bus speed manipulation and it supports up to 10.5x mulitipler on the P3's, just update the BIOS to get the new multiplier. It should be cheap and it's a stable slot 1 board now, since they don't make them BX boards anymore. No on board sound or video, but does have an extra ATA66 IDE ports. Only thing is that if youf FSB speed is going to exceed the 105MHz bus, then the AGP port may have trouble w/ dividers.
I have my Celeron 633 o/c to 950@100mhz, and it's running pretty good w/ my ATi RAGe fury. I just setup another computer w/ a Soyotek 6VBA w/ the VIA Apollo 133 chipset with pretty much the same setup except for the new board and new p3 667 on the soyo mobo, but when comparing them on Counter-strike, I get max. 71 fps on the ABIT, but only about 31 fps on the SOYOTEK. It kinda ticked me off that the Apollo Pro 133 wasn't as fast as the BX chipset since I was gonna upgrade to the Soyo.