my favorite would be Ballys, highly underrated but now that it is part of the evil empire say goodbye to Ballys and all the special treatment that i was able to get.
I have stayed in almost all of them, except the really creepy ones like the casino royale, or the off strip ones like Sams town.
I would have to say the Nugget is at or near the bottom of the list. I here it has improved, i hope. Some of the old ones i liked, were the Dunes, Maxim, Hacienda.