Took a walk up Ocean and down Collins last night. There are a TON of little boutique type hotels all through South Beach, most with bars/restaurants or retail space under them. I think there are more than a simple Google search will find.
Ocean is where most of the party scene is, tons of people out and loud music and good looking hostesses trying to hook you into their establishment. Collins, although only one street over, is much quieter (more retail space). In my limited experience the hotels off Ocean are more expensive (it's the place to be right?). But Emo EMAW says to save some dough, stay off Collins (especially if your folks or whatever will be with you), and stumble your drunk/high/tripping ass back from Ocean.