Your best choices are probably the Hilton and Royal Plaza, unless the Courtyard or one of the others has a much better price. I've heard good things about both, but I've never stayed in either. I have stayed at the Palace (years ago!), and it's also a nice property, though I have read a handful of poor trip reports about it in the last few months. Reports on the Courtyard, Grosvenor, and Best Western are mixed, with many guests reporting they are nice for what they paid, but (apparently) not up to WDW standards. Of course, I've even heard a few complaints about the Polynesian (!), so take that into consideration.
I'm sure others will have firsthand information. Have a great trip!