I would recommend Gigabyte's motherboard if you don't want to overclock your CPU and seeking for stablize system.
If you want to overclock, then I would recommend DFI. MSI is also another choice, but you have to be fortunate enough to get the good one.
Asus..... not that good lately.
Also, what's the chipset for your Ram. I would strongly recommend using Samsung's or Hynix's chipset. I don't know why, but it seems that if you want a stable K8 system you have to get the Korean chipset.
My kingmax ddr ram is using Hynix D5