Rush will top my list. There are a number songs that are not my favorites, but overall, I love watching and hearing these guys play.
Joe Satriani is on there, too. Even though I'm not a guitarist, I can appreciate his artistry and technique. A friend of mine described Joe's music as "singing with a guitar." I think that sums it up pretty well.
Dream Theater is up there, even though I'm not a die hard fan. Their stuff is very complex and technically brilliant, but sometimes the musicality suffers. I really like their new drummer, though. Mike Mangini is fantastic.
Going back, I'd include Kansas, Bad Company, Led Zeppelin, Heart, Boston (1st album), Aerosmith ('70's), Devo (they amuse me), some Uriah Heep, Saga, Shooting Star, Jimi Hendrix, Stevie Ray Vaughn, ZZ Top, and others I can't recall right now.
Yeah, I know the list is overly populated with artists from the late '60's through the 70's. To my credit, some of them are still making music today. (Okay, not many, but still...)
I'm sure there are more, but those are the ones that raced to the forefront of my mind to get a good seat.