congratulations!! Las Vegas is an amazing playground for adults there are so many things to see and do and a lot of stuff that is free to see :)
I love the city and go usually twice a year I have been there about 16 times and there is still so much that I haven't had a chance to see.
If you are looking for a good show take in David Copperfield he is amazing (and this is coming from someone who isn't a huge fan of illusionists) and Mystere - Cirque du Soleil production is really good (one of my personal favorites), also make time to go out to Freemont Street (old Vegas) even if you only have an hour or 2 to spend there. It is what Vegas is really all about.
There are a couple of Tickets 4 tonight booths on the strip where you can get a lot of great show tickets for half price
you can pm me if you want some info