The VooDoo lounge on the 50-somethingth floor of the Rio offers great nighttime views of the Strip (from just off it so you can see it all at once.
I don't know if it was killed in the recent conversion to being Planet Hollywood but the Spice Market Buffet at the Aladdin was a very good backup to the Bellagio.
The pirate show at TI is definitely not worth anybody's time.
If you're going for a conference and have a small daytime group and want to impress with some local knowledge get a cab to take you to
Luv-It Frozen Custard in the shadow of the Stratosphere. Generally considered the best frozen custard west of wherever it is that traditionally prides itself on frozen custard.
I don't generally do shows in Vegas but O is fantastic, the drag queen dinner theater thing (forget where it is but it is in a strip mall down at the Strat end of things) is boring, Tony & Tina's Wedding is dreadful. Penn & Teller's show at the Rio is great.