Willy - My wife and I and our friends try to go to Vegas 2 or 3 times a year.
Some things I would definitely do.
I would say, if it is your first time in a long, long time, go to as many casinos on the strip as you can. They all go way over the top theme wise, and have eye candy galore to check out. You'll like some, you'll think others aren't your bag, and so on. The atmospheres are widely different, as is the clientele. From there, you can branch out and decide to see more.
Plus going in all the casinos is free.
-Pay to go to the observation deck of the Stratosphere. If it isn't windy, it's an absolutely amazing site from the top.
-Personally, the New York-New York Casino is my favorite. The way it's setup, the atmosphere, the bars & restaurants, that's always my choice. Paris Las Vegas is a close second.
-Watch the Bellagio Fountains. They go off every 15 minutes after dark. Seemingly different music & formations every time. Worth catching a couple of times while you are there.
-Take a ride in the Gondolas in the Venetian. It's an impressively setup Casino, to match Venice - probably the most intracite of any of the Casino designs on the strip.
For food - Emeril's Fish House in MGM is excellent but pricey. We also liked Il Fornaio in NY NY like edabbs recommended.
For Gambling - you Can't beat Downtown(Old Town) Las Vegas or some of the really old Strip Casinos like Barbary Coast. My wife and I always spend a good amount of time in Barbary because they have all the newest penny slots for her and all the table games have low minimums for me.
You'll really struggle to find anything less than $10 minimum bets at any tables on the strip at the big casinos.
Check out this site as well
http://www.cheapovegas.com/index.php
Really good information about each casino - the food, the attractions with some candid opinons.
Good luck - and report back to tell us how it went.