I can't believe 2 of these 3 in state runs haven't been mentioned:
1) Slaughterhouse- fun eddy hopping through boulders, cheep thrills @ falls, fun surf wave near the end;
2) Encampment- fantastic wilderness run with a rapid named "Damnation Alley"- how can you beat that?!
3) Ark from Clear Cr. confluence to #5- the steepest section of the Ark, and the rapids below Pine Cr. are a blast.
Out of State:
1) Forks of the Kern, CA- classic IV+ wilderness run tons of really fun eddy hopping through big round granite boulders
2) Cherry Cr. run on the Toulumne- back in the day it was the tespiece for class V boaters- OK- I'm dating myself...
3) The Grand- best boating vacation ever.
Out of Country:
1) Fuy, Chile; some of the funnest class IV on the planet punctuated by 10-30 foot waterfalls.
2) Upper Paquare, Costa Rica; slept on the rocks at the take out after 3 class IV/V gorges in 10+ miles.
3) Hollin, Equador; After running the first rapid in this 2 day jungle run you are locked in for the next 35 miles of class III/IV with one portage in there somewhere.