Not only is SLO an awesome town not far from some great beaches, but The Madonna Inn has 100+ entirely uniquely designed rooms (which sorta calls for visiting a ton of times), some with odd features like waterfalls, turret rooms, and rock walls. The main restaurant is an upmarket steakhouse - I've not had a steak beat any of theirs yet. There's also a cake deli of sorts and my wife testifies that their cake is unbeatable. Oh, and there's an awesome menswear place on the top floor..
Last, the entire place is designed in a totally crazy and idiosyncratic style that I've never seen replicated anywhere else. It's certainly not to everyone's taste, but I'm more blow away by how unique it is every time I go there than my opinion of the decor per se.