Crawford Electric Supply Company

Been using them for over a decade from their old location to the new location and they are a solid electrical supplier.  They also carry Klein tools which are the industry standard along with power tools from Milwaukee and Dewalt.  

Of course, something keep in mind is that they are not a lighting supplier so if you want really fancy lighting fixtures, you need to go to a dedicated lighting store, but any sort of electrical device or wire you need, they have it.