dc--I'd argue for Ra to be one to avoid, but to each their own! I'm assuming you've done 54 (my fave). Have you checked out The Beach? (It's across the street from the Las Vegas Hilton.)
newbie-Are you flying or driving to Vegas? If you're driving, stop at the outlet mall at Stateline for a break.
Watershow @ Belagio is sooo pretty! I have to insist that you do the Slingshot on top of the Stratosphere. It's completely nerve racking to think about but it is the absolute biggest adrenaline (sp?) rush that I've EVER had! I wanted to ride it all night.

Yup, night! They sell multiride tickets so you can keep getting back on. Plus the view is gorgeous up there.