My favorite crit would have to be the Ballard Crit in Seattle - first "big" race I won (as a 4 & a 3). Course & atmosphere are pretty rad; for Seattle anyway.
Two runners up would have to be the Cascade crit stage in Bend - mostly for the atmosphere, since the course is pretty basic - and of course the San Rafael crit, for obvious reasons.
Runner-runner up is Cat's Hill - love the course, unfortunately it doesn't love me back...
As for RR's, I actually do like a few: San Dimas RR course is fun, and Mason Lake in WA was always fun too.