- ASUS A7V400-MX SE
or 2. ASUS A7S8X-MX or
Don't know about Via's support for linux but SiS sucks. A7S8X is going to give you nightmares if you plan to run linux on top of it.
My experiences have been with ASUS A7S 266 VM which has gone bad twice an year and now the service centre are asking me to get distributor challan. I think buying from Rashi Peripherals (http://www.rptechindia.com) would be better considering they are among the distributors. As far as possible seek A7N8X motherboard.
Regards, Peeyush