I have been to Vegas several times for work. Thoughts on places I can recall staying at, from worst to best:
MGM Grand- Small room, 30+ minute walk from room to parking garage, horrible traffic around the hotel.
The Golden Nugget- Old hotel on Fremont Street. Nice, but felt like a place for old people. If you pulled up in your 'lac, you would be treated like royalty.
Ballys- OK. Don't really have any strong memories of it, positive or negative.
Casino Royal- If you are a Star Trek NG fan, it is kind of cool to know you once stayed at the Casino Royal. The hotel isn't much... kind of like a Motel 6 style 2 story thing behind the Casino, but it was very clean, the people were nice, and it is one of the only cheap but clean places on the Strip. If you want to be on the strip, but retain TCB status, it is a good choice.
The Rio- If in the budget, this is my favorite. Every room in the place is a suite and the help is easy on the eyes. It is located on the other side of the freeway from the strip, which I found to be a big Plus. They had free buses taking you to the strip every few minutes, but if you wanted to drive somewhere other than the strip, you don't have to deal with the traffic. If you get a upper floor room on the strip side of the hotel, you get an incredible view.