I was stationed out there for 2 years, and it's an amazing place to visit. For eating and such, I recommend the Fisherman's Wharf - a place called Dominco's is really top notch. The owner will walk around to the tables and make sure everything's good, they buy all their seafood from local fisherman and it's never more than a day or two old.
Also, if you just want a place to hangout/drink/socialize, I recommend Indian Summer - it's a little hole-in-the-wall place down by Fisherman's Wharf. It's a hookah bar that serves authentic Indian food, and is outstanding. For more on the drinking side, I recommend going downtown to the Mucky Duck or the Brit. The Department of Defense Language Institute is right up the hill, though, so you're going to run into your run-of-the-mill young military guys/gals.
One more thing - you HAVE to get "The Marine Special" from Compagno's, it's a sandwich shop and is famous. You'll definitely have to wait in line, but I can guarantee that it's going to be one of the best sandwiches you'll ever have! I used to get one at least once a week - it's on Fremont Blvd going up the hill towards DLI.
Oh and a drive down Big Sur is a necessity - it's gorgeous! I'm sure you've already been though, hopefully
If you have any questions about it, let me know!