CPU support for Web hosting

So a friend of mine and I are trying to start a hosting company, and we're trying to figure out what kind of resources we're going to need in order to do that. Specifically, my friend wants to know how many websites an Intel xeon e5-1660 can support at once and how much ram and hard drive space we would need in order to do that.

Also, would it be better to go with an i7 or amd opteron instead?