My fave was probably the Asrock 939 Dual Sata2.
http://www.asrock.com/mb/overview.asp?Model=939Dual-SATA2
I was upgrading from an nforce 2/athlon xp system with an x800 (still good at the time, but agp obviously) and didnt want to buy mobo, cpu and gpu all at once, or have to buy an nforce 3 board and then a pci-e mobo when i upgraded the gpu.
on a side note, i wonder if those cpu upgrade boards (am2) for these support newer phenom II's?, while i doubt they do, it would be awesome to see a 6 core on such an old mobo
Also, its a real shame nvidia bought uli, they were a company with some interesting idea's, i think it was another chipset of their's running sli that made nvidia buy them, and as they're out of the chipset business (other than ion) clearly they didnt make good use of the acquisition.