there is so much to see & do there,unless you are on honeymoon, you only want somewhere to sleep, the rest of the time you will be out & about. I have stayed at the following Imperial Palace [ basic but very central you can walk tolots of other hotels dont need transport [ bus or cab], New York, New York, Luxor,MGM, Excalibur all these four + Mandalin Bay have a linked walkway and the standard of the rooms are good. The only one that was grotty was when we stayed at the Circus, Circus.
The Bellagio, Wynn & Venetian are of a much higher standard, but will you spend much time in there ? if not use the saved money to go and see some wonderful shows.
I think the Stratosphere is just a wee bit too far out but thats my opinion. Anywhere on the strip is fine.
Dont forget to spend one evening in old Downtown see a show , eat down there its much cheaper than the strip also recommend the buffet at Planet Hollywood hotel, its a bit dearer but oh boy is it worth it, so is Treasure Island buffet. Your definately spoilt for choice and dont let me start on the shopping bit -------
just go and have fun.