Got Holly's autograph the first time I was in Vegas - her show is amazing... seen it twice.
Personally, I liked the production shows the most - e.g. the Lion King, the Phantom of the Opera - not sure if they are still showing still.
Each casino has it's own unqiue attraction - personally I found the indoor canals in Venetian the most interesting.
Hope you have fun!
Unfortunately, the Lion King is gone. I believe it closed last year. Phantom of the Opera is scheduled to close in Sept. I've seen both and they were great shows.
Le Reve @the Wynn is another good show. It's not a Cirque production, but it's similar.
If you're an Elvis fan, "Viva Elvis" @the Aria is going to close in August, so this may be your last chance to see it ...another Cirque show is scheduled to take it's place ..."Zarkana".
Terry Fator @the Mirage - I haven't seen his Vegas show, but it's at the top of my "to do" list.
If you never been downtown to see the Fremont St. Experience, it's worth seeing at least once.