Denver's pretty big but Mr. B's if your downtown or stapleton. Small Batch, by the stadium as well. Applejack's if you are out on I70. South Denver already mentioned above.
I've been all over Denver. My suggestions are as follows:
Grapevine - probably the best overall
Davidsons (south side) - very nice place, a little more upscale
Small Batch, Mr. B's, Mile High (in Belmar, not by the stadium) - all reliable