95% of Grateful Deads music is pretty marginal. The thing is though is that almost everything they have ever done has been recorded and they've been around a long time and played allot of concerts. The math is pretty impressive. So if you can weed through the nonsense and find them on a good night, their playing can be magical. Not so different from the great live jazz bands when the players have those great nights. It's also been my experience that the great GD recordings that I have are all about Jerry Garcia playing these inspired improvisational threads. Some people think it's mindless noodeling but I find it a very high form of art and sheer musical beauty. How come it's OK to improvise on a trumpet or piano but when a guitarist does it, it's mindless noodeling??
I've never understand Clapton bashing. He has a great voice, written a fair share of really great songs, he can play alt country, blues, hard rock, ballads and everything in between. Just check out the DVD tribute to George Harrison when he sings "Something" and completely out classes Paul McCartney. You don't see him running around craving attention like McCartney and Steve Wonder. What's not to like?
I also will have to disagree about Wilco. They are one of the better bands out there right now. Check out their last appearance on Austin City Limits.