I know that Vegas is just an explotion to the senses. There are always bells ringing, lights flashing, quarters dropping. There is so much to see that you can't possibly see it all. My advice to you is this: look up. Take the time to look at what's over your head.
The most astounding ceiling is in Ceasar's Palace, where the "sky" morphs from morning, to high noon, to dusk, to dark -- all in an hour's time. If you didn't know better, you'd think it was real.
Mandalay Bay features glass flowers surrounding the light features in the lobby. Perhaps reminding you to visit the botanical gardens, but I think it's just Vegas flash.
Paris has the cathedral-looking ceilings, and the Venetian has all the splendor of a Roman arch.