I have stayed in most of them at one time or another. My thoughts, from one end to the other. Mandalay Bay, nice, but the middle of nowhere and the table limits are insane, especially on weekends. Too far away. Luxor - Shithole, pure and simple, but it's cheap. Excalibur - same story as luxor. Trop, see luxor. Hooters, not even worth mentioning. MGM, not bad, if you stay in the Sigature or a suite. New York New York, marginally better than Luxor, but still pretty lousy. Monte Carlo, about the same as NYNY, but not as tacky. New ones: Vdara, Aria, Cosmopolitan, all new which is nice and if you have the email deals, the prices are not too high. I liked Aria the best of the 3, mostly because I was comped there, so take that into account. PH, much better now that it used to be, again only the tower is worth it tho. Paris - tacky and overpriced for what you get. Bellagio, tired and overpriced. Caesars, classic, but too pricey for the value. Same as the luxor, but in a much better location. Flamingo - 1978, awesome. Today, tired. Mirage, so tired. TI, they have tried to update it, but it's like they slapped some paint on it and upped the prices 50%. Venetian/Palazzo, very nice, if you can get the rate down. Wynn/Encore - same as the Mandalay, but on the other end.
Off strip, the hard rock is a decent choice if the rooms is near free. Rio, same thing. Palms is the next on my list, if only for the playboy connection.
There are a few I didn't mention, the Strat, Harrah's, Imperial etc, that's because you should never stay there, even if it's free.
Downtown is not worth the effort. Go see the light show, get the hell back to the strip before you get mugged. Whereever you go, get on as many of the hotel email promos as you can. My last trip, I had 2 nights free at Caesars before I even got there, and then I got the other night comped after being on the tables for about 4 hours. 4 nights and airfare aint bad for 600. The goal in my experience is to try to keep your daily nut to $100 or less, leaving more money for gambling, strippers and ladies.