Absolutely the Grand Californian! The pool is beautiful and the waterslide is fun though nothing spectacular. The hotel and grounds are gorgeous; in particular, the lobby is spectacular. They offer lots of little extras to guests, like gold coins on the pillows, activities each day, childcare (for a fee), and of course they have a special entrance to CA, which is very handy!
I really, really love the
Disneyland Hotel. It is my personal favorite! But if you're looking for a "fabulous hotel," I think you'd prefer GCH. It is more upscale, while DLH is more family oriented and Disney-esque. They have topiary animals, characters in the lobby, a very cool pool with lots of landscaping and a pirate ship (which isn't something you can play on but looks great!). They have waterfalls and koi ponds and second pools and on and on. It is further from the park but a nice walk through DTD and it's also very close to the monorail.
The Paradise Pier Hotel is nice but not fabulous, IMO, and I wouldn't pay resort money for it. If they have a good special, then ok, but otherwise I'd go with GCH or DLH or stay off-site. At the times I go, it has only been $10 less per night than DLH which isn't worth the savings to me.