Definitely Corvus... I get about every second bag of coffee I consume from them (the others come from Novo, because that's what my local coffee shop here in Boulder carries; which is also good).
If you're into espresso, the Everyman blend is outstanding.
As for my Top 5?
1. Chromatic (Santa Clara, CA)
2. Stumptown (Portland)
3. Black Sheep (Bishop, CA)
4. Crema (Nashville)
5. Corvus (Denver)
5b. Four Barrel (San Francisco)