You may want to look into the P4S533. It's a SIS645DX chipset. To me, the board is 20-25% faster than a P4B266-E or P4T-E, seat of the pants, e.g. stuff like booting up an OS and partitioning/formatting and stuff.
I got a P4S533 1.03 Rev. board + audio and LAN for $108 from Multiwave. I get the same overclock as on a P4B266-E board (as good as it gets), with a tad less voltage: 160 FSB at 1.775 volts.
It has mem ratios of 1:1, 3:4, 3:6, and 4:6 (I think) below 133 FSB, and 1:1, 4:3, 4:5, and 4:6 above 133. Somebody said you lose this >160 but I have to check.
It has an overvolt jumper that increases your CPU vcore by .15 volts (not quite the 0.2 advertised), but this means you can get up to a 1.85 vcore in the BIOS without vid pinning!
It has adjustable VMEM of 2.6, 2.7 and 2.9. The only drawback of the board is the FSB only goes to 166 in the BIOS, but that's enough for most people.
So far the board is totally stable in 3D at 160 FSB, the limit of one of my 1.6a Northwoods. I've been using Intel chipsets so far but I am damn impressed with this SIS board. I'm still burning in my Samsung PC2700 in hopes of doing 200 mhz, 2-2-2-5-1, which is what I would get at 160 FSB, 4:5 mem ratio. So far it will only do 2-2-2-5(4 actually)-1 at 180 mhz.