Ive always had ASUS boards and have only had slight trouble (USB burnt out and I had to get a PCI card..)
Ive been wantign to get a DFI board but I doubt that its gogni to happen in the near future.
Overall those are my top two, however Im waiting to see what happens with ASUS because Ive been hearing for alot of people that they are relying on their name and reputation for their boards and not putting in as much QC.