Keystone is good for both beginners and experts, but there isn't much nightlife in the immediate vicinity. Same with Wolf Creek. However, Keystone is close to Breckenridge, Dillon and Frisco, where there is plenty to do after riding.
Breckenridge is good if you want a big town, lots of night life and lodging within walking distance of the slopes. Its pretty touristy, though.
Vail has arguably the best terrain in Colorado, but much of it is too advanced for a beginner. Good night life and plenty of hotels, though.
Buttermilk in Aspen is where they hold the X-Games, and its a bit ironic that they hold an extreme sports event at a beginner mountain that has no expert runs. You simply can't beat Aspen for night life, but lodging at the base of any of their mountains is pricey. Aspen has a free bus system connecting the town with all of the four mountains.