Cheaper outside the park, any of the hotels on the roads in have been fine. I've stayed in a few and never had a bad night.
Inside:
The Ahwahnee Hotel, The Yosemite Lodge at the Falls (generally both require reservations months in advance), Curry Village.
We've also stayed at the Lodge and found it enjoyable. If I had the foresight and an unlimited budget, the Ahwahnee would be a great place to stay. Never stayed at Curry.
More details from tripadvisor here:
Yosemite National Park: Places to stay in and near Yosemite - TripAdvisor