it depends on which memory u want to use...m2n-e and crosshair are good but not needed I would say any asus am2 is good though...stay with asus and u will me ok...also make sure the board is am2+ compatable so u can get the new amd phenom quad core that is comming out later this year...
my main problem is that i cant find memory that fits the M2N-E. I try the QVL and turns up with nothing helpful, i want to hit 8GB memory at some point this year, but cant find 2GB sticks that fit that board or the ASUS M2N32-SLI Deluxe.