Q6600 versus a Xeon Quad core

[Sutorx]

Looking around i not a lot on this topic for a server, im looking at building a server and wondering what the difference between say a q6600 and a Xeon Quadxeon quad? or even go with a penyrn, kind of on a 250 budget here. Just wondering what one i should get, just going to be a file server 8gb of ram, sata raid 5.

Thanks