perferably something without a VIA chipset though.
As joefriday said, the AsRock 775i65G gives you what you ask for. Just buy it retail so you get Rev 2.0 or later which works with Conroe chips. Earlier ones don't.
The advantages of this board:
A). It lets you keep your AGP card and DDR400 ram.
B). It makes a cheap (and Throw-away!) path to upgrade to a Conroe.
C). It FORCES you to get a good mobo when it's time to upgrade you videocard, rather than try to put a high-speed PCI-E card into a slot that only runs 4 lanes (like the VIA PCI-E does).
Drawbacks:
A). It is slow. The ram and video also will hinder you getting the most from a new Conroe.
B). You will have to throw it away when you move up to DX10.