I haven't been to very many, but the ones I have been to were good. They'd have been better if I weren't a bit crowd-phobic:

The Eagles
Fleetwood Mac
Chicago
Santana
The Rolling Stones
Neville Brothers
Linda Rondstadt
Heart
Willie Nelson
Dixie Chicks
Nora Jones


Also,
The Dallas Symphony
New York Philharmonic
London Philharmonic
Boston Symphony
National Symphony