Just about anything new will handle virtualization. Stick with a name brand like Asus, Gigabyte, etc...
How many hosts?
What type of RAID are you considering?
A word of caution... Intel / Sandy Bridge are GREAT processors, however for virtualization the number of physical cores is more important than top end processing speed (hyperthreads are not physical cores). The AMD Phenom X6 is a good option depending on needs.