Make sure to get a motherboard that is fully compatible with upcoming AM3+ processors, like the new 8 core >3ghz AMD's. Will substantially improve the future upgradeability of the computer and should make it hold value for longer. AMD Bulldozer expected later this year.

http://event.asus.com/2011/mb/AM3_PLUS_Ready/

http://en.wikipedia.org/wiki/Bulldozer_(processor)