In no order:
XTC ( I only saw one other vote for this group, where are all you Brits?)
Greenday
Ben Harper (I'll get crucified for this, but he's one of the best guitar players out there, and his songs are entertaining and have meaning)
Weezer
Older Peter Gabriel (though I love the Barry Williams song's mocking of American "culture" and will be buying the new CD next week)
Smithereens
Devo (perhaps the greatest cover ever is their version of "Satisfaction")
I know I'm missing someone here, but I should get back to work....