Hi,
One MB that has caught my eye is the Gigabyte GA-7VT600-L, a Via KT600 chipset board. It also has integrated audio and LAN, using Realtec ALC-655 audio chipset and Realtec 8101L 10/100 LAN chipset. I'd appreciate it if any of you know of how well this board and these chipsets are supported in a modern Linux if you'd let me know. This Gigabyte board can be purchased today for US$63 from newegg (not a plug, just a fact).
I have this same board in a machine at work and while it works fine, the VIA chipset tends to muck up frequently (that said, I've never liked VIA or SiS). The ALC65 is a bog standard AC97 device and the network works fine, though again, I never like onboard networking (though it has becoming a hell of a lot better recently), so use a Realtek 8139 100base nic. Much nicer IMO.
I would avoid AOpen motherboards - from my experience they give nothing but trouble. Asus are pretty neat though, but the best out there are gigabyte mobos.
TTFN
Paul