I don't know how to separate "current" from "all time". The numbers may change; I'm loathe to just list what I'm listening to now, since Fish and Brand X are probably not in the upper echelon, but I've been listening to them a lot lately because I made some purchases...
1. The Beatles
2. Genesis
3. Yes
4. Iron Maiden
5. Kiss
6. Deep Purple
7. Marillion
8. Cheap Trick
9. Sabbath
10. Dream Theater
Too many ohers that should be here, too: Night Ranger, Widespread Panic, the Dead, Rush, The Rolling Stones, Zeppelin, Billy Joel, Elton John...
This is too hard.