The best all-round Slot1 chip set is 440BX originally designed for 100MHz FSB Pentium II. There are last-gen 440BX boards that overclock the chip set by default to 133MHz FSB operation. They exist because Intel never released anything better for Slot1/Socket370, being busy playing with RAMBUS. However, running BX at 133MHz results in 89MHz AGP bus, default for which is 66MHz. Some videocards don't like it at all. That's where VIA Apollo Pro 133A comes to play, boards like ASUS P3V4X. They perform on par with 440BX, sometimes slightly slower, but offer 66MHz AGP at 133MHz.
The result is, a 133MHz 440BX board is the best you can have for a PIII at stock clock, if your videocard can handle it. If you wish to overclock, VIA Apollo Pro 133A is worth considering.
P.S. Just FYI, fastest Slot 1 processors, 733MHz and above, are a rare breed. Pentiums were introduced on Socket 370 (previously Mendocino exclusive) at the time of Coppermine. Socket 370 CPUs were cheaper to produce and are much more common. You can use the Slotket adapter to mount a Socket 370 CPU in Slot1 machine, but that kind of kills the point.