I live in Vegas, so I haven't stayed in too many of the hotels. But DH and I stayed at the Mandalay Bay once (his office christmas party was held there and they got everyone a room) and our room was very nice. The Venetian and the Paris are supposed to have nice rooms too. I saw them on Great Hotels. I've not been in the rooms but I've been to both casinos and they are really pretty, especially the Venetian. If you are looking for inexpensive rooms, try Excalibur, Circus Circus, places like that. They aren't all that nice room-wise, but they are okay.
Try booking a package on Orbitz.com or one of those sites and you can usually get good deals.
We were just out on the strip last night (we never go to the strip, but our kids our out of town for spring break wtih the grandparents). We went to the new Margaritaville cafe that just opened this past January. VERY COOL. It's at the Flamingo and you must check it out. We actually have a lot of themed restaurants, like Rainforest Cafe, ESPN Zone, Nascar Cafe, Harley Davidson Cafe, etc. All are fun to eat in.
Hope you have a great time.