Great ski area, great nightlife and not too expensive
Some slow lifts
In my opinion Sauze is the best ski resort in the Milky Way (not the galaxy, this really is the name of the ski area which also comprises Sestriere, San Sicario, Claviere and Montgenevre). Is has just about the best ski area, including lots of tree lined runs and off-piste territory combined with a lively nightlife.
The ski area really is massive with good links to the other resorts, including the opportunity to ski into France. This being Italy none of the runs are really difficult, including the Olympic runs, just a lot of fun.
Nightlife can be as crazy as you want it. There are lots of bars, with happy hours and lots of live music. This being Italy prices are not too high.
On the downside the lift system is a little antiquated but new lifts are coming in winter 2011.