Okay Dizlover,
Disneyland itself is pretty close to the Magic Kindom at Disney World with a couple of rides from other parks thrown in. California Adventure is unlike anything at WDW but can be done in a day. In order to see and do everything I would want to stay at least 3 days - 2 for DL and 1 for CA. You can get 3 day hopper passes. DL is BEAUTIFUL at Christmas time and well worth the trip.
As far as where to stay, well I always prefer to stay at The Disneyland Hotel, where they have a wonderful themed "NeverNeverland Pool" and there is a character breakfast at Goofy's Kitchen which is an all-you-can-eat buffet - Very good and VERY fun - IMHO. I have stayed at other places though, this year when we went we were there for 10 days (we have family in the area) so we rented at The Dolphin Suites - which were pretty nice for the price - they are time shares that rent out- we had 2 bedrooms and a small kitchen and patio.
If you will have a car you might want to stay some where that has a kitchen, etc. To save on food bills. They are all kinds of hotels around there with all kinds of prices. So depending on how much you want to spend and how close you want to be will determine where you should stay.
Hope this helps you!