Looks like Jay answered the question pretty well. The i845PE is the chipset used in motherboards, sorry for the confusion. I'd recommend the Abit BE7, it's a great mobo for about $100. The Asus P4PE is pretty good too. Both of these I mentioned are overclocking friendly, have lots of great features, and have all the settings done within the BIOS.
Since your current system does support the Tualatin, I guess that's your call. But, without an AGP slot and with SDRAM, I'm not sure it's worth upgrading the CPU, unless you can sell your old CPU for a decent price to compensate.