you know me, always lookin' for a new way to get high...
I first thought Stratosphere or Wynn, but figured I'd check with the locals see if anyone has a hot tip.

does not have any rooms up high. That tower you see is a restaurant, amusement park, viewing area. The hotel itself only goes up about 15 floors.  
For the budget conscious great views try The Palms or the Rio. Request a high floor strip view.  
Break the bank at the Cosmopolitan.  

Have very nice rooms with a great view if a hotel without a casino doesn't bother you.
You can ask for a corner room up on the higher floors.
Aria is a very short walk from Vdara if gambling is your thing.Also,try Cosmo or Aria as well they have rooms that are high up with a review.
Good luck to you.
Stratosphere really doesn't have a great view IMO.

Then, yes! Vdara. Absolutely!

Last few times I have stay at Mandalay Bay I have upgraded to a kick ass sweet for a few bucks a night.  Mandalay isn't the marquee location it was 5 - 10 years ago... but its still a great property and very hobby friendly.  Any of their end rooms suite or not facing right down the strip is on of the best views to be had.  With a little preplanning you can get great deal there..

used to visit Vegas 3-4 times a year , always stayed at The RIO , the VIP suites on higher floors of Masquarde tower  offer a great view , especially at dusk , as the strip begins to light up !!

I think those rooms at the Cosmo have the best views, with the fountains, but also a big part of the strip.