Lake Tahoe has a ton to offer. I just came back from my 7th trip there in the past 5 years and I am ready to go back. There are numerous ski hills, my favorite being Homewood. It is a local kind of hill that doesn't have high speed quads, but it also doesn't have long lift lines or lift ticket prices that are through the roof. It has the best views of the lake. I always take at least one roll of film while I am there.
At night, I like to try my luck at the casinos in Stateline and occasionally go to a show. We caught Blues Traveler at Caesars on this last trip. Even if you don't ski or gamble, Tahoe is worth at least a weekend trip. You can spend a whole day just driving around the lake and you can find any kind of accommodations, from budget to luxury.