The Grand Californian Hotel is the place to go if you can afford it! It is nearest to the parks and Downtown Disney. It is a superb hotel and the cast members are top notch. It is the spendiest and nicest, but if I can afford it this is where I will stay. And I always tell folks to at least wander through it (if you stay at the PPH then you should walk through it almost every time you head to the park for a wonderful shortcut!)...
The Disneyland Hotel is the truest spirit of Disney in hotel form, so it is pretty awesome. It tends to fall in the middle price-wise and quaility-wise. Great hotel... You have to go sometime!
Paradise Pier is great too. It is cheaper, noisier and isn't quite as nice as the other two hotels, but it still captures the important essences of the Disney experience.
Another thing to keep in mind, if you have the $$$ then you can splurge a bit and have an excellent trip. Instead of staying at the GCH, you may do a stay at the DLH with concierge service... I have not done this, but I have heard rave reviews from folks who have stayed at the concierge level at the different hotels...
