Vegas, baby!
I head to Vegas about once a year, and it's always a good time! Here are some suggestions...
Places to eat: If you like the typical vegas buffets, try the one at Mandalay Bay--it's amazingly great food, plus the best desserts around! Also, the buffet at the Rio is pretty good too, something like 9 different areas of food. There's also a great french cafe in Paris, next to the shoppes.
Sights: I've mostly stayed on the strip, and there's tons of stuff to keep you busy there. Free shows at the Bellagio, Mirage, Treasure Island.....just walking around the new hotels like the Bellagio and the Venetian is awesome. But don't waste your time at the Stratosphere! Fremont street is fun too, especially if you like to gamble for really cheap (fifty cent roulette at the Four Queens Casino!!!).
Oh, Hoover Dam is beautiful at night--I suggest a sunset drive there so you can see it all lit up--super impressive!
Hmm, other things...There's the M&M Chocolate factory there (Ethel M's, I think) you can tour. Raging Waters water park is pretty cool. Then hit the clubs at night--Ra and the Rum Jungle are awesome.
Hope you have a great time--I always do!