You'll find a lot of budgeters arguing that you can enjoy the magic just as much, and at a lower cost, if you stay at a site off the resort. I'm sure you can enjoy the magic ALMOST as much. Personally, I don't want to risk it. I also don't mind that I may have to walk just a few minutes more to get to the gates than some of the offsite hotels. Strollers were invented for a reason.
The perks of staying at the resort are enough for to opt for one of the three hotels that are part of the Disney property. If you stay on site you get to enter one of the parks one entire hour earlier than guests who do not stay at the resorts. You can use this time to hit up some of the more popular rides and secure fastpasses.
If you are insane enough to go during a holiday when the parks are most likely to reach capacity (think Christmas week, Thanksgiving, Fourth of July...) resort guests do not get turned away even when other guests get turned back for full capacity (I imagine the resort built some sort of safety number to allow for maximum capacity with resort guests included...).
The hotels are nice. The cast members are even nicer. Quite frankly you will be hard pressed to find another hotel as close as these hotels are to the park with pools half as nice.
The hotels do cost more than you will spend at most of the offsite resorts, so if your budget is really tight one of these resorts may not be an option. That being said there are several off site resorts that are nice too, I'll discuss those in another post.
The three resort hotels of Disneyland and California Adventure:
This is my personal favorite. It has the classic Disney feel and as the original Disneyland Resort hotel, it should. The hotel was finished a remodel in early 2012. The results are stunning. The rooms are very nice, clean and comfortable. The headboards light up and the mattresses are insanely comfortable. A silly note, but one of my favorite parts of the room, was the retractable clothes line in the shower. It was super easy to use and provided a place to hang up wet swimsuits. Also, do not be afraid to pack up those shampoos and conditioners (they smell AMAZING) and its like taking a little piece of Disney with you when you go.
This hotel is very close to Downtown Disney. If you don't mind a little extra walking, stay in the Frontier Tower. This tower is behind the new pool area. If you get an upper level room with a view, it's totally worth it. You will be treated to a lovely walk back from the parks each night. The live music from Taradoga Terrace is relaxing and a great way to end your day. It literally feels like you are in another world.
This hotel is priced the lowest of the three. The charming California boardwalk feel really is a lot of fun. The Paradise Pier is also home to my absolute favorite character dining, the PCH grill. This hotel is one tower, which is nice for getting around the hotel. Paradise Pier. The hotel features a little theater that plays kid's movies and an arcade as well as a roof-top pool.
Views of California Adventure are pretty awesome from this hotel and you are within very close walking distance of the Grand Californian, which has a private entrance into California Adventure. The rooms are a little larger here than at the Disneyland Hotel so if you need to bring a playpen, you will probably have a little more moving around room here. As with the other hotels on the resort property, you get to use the private entrance at the Grand Californian to enter California Adventures.
The only complaint I have heard about this hotel is the elevators get pretty jammed in the morning and at night. You may need to plan a little extra time or be willing to take the stairs.
The Grand Californian is very high-end. If you want luxury, this is probably the hotel for you. The lobby is absolutely stunning. The dark wood interior is open and large. It really is beautiful. This hotel is the closet of the three to the parks and has a private entrance into Cali Adventures (any resort guest can use it). The Grand California hooks directly to downtown Disney, so the walk is really quite short. But, you will pay a bit more for the extra convenience.
The Grand Californian has a high-end spa as well as three pools and several restaurants. This is the only resort at Disneyland for which you can buy Disney Vacation Club points. The Grand Californian is the newest of the three hotels and the only one Disney actually built. The hotel was constructed in 2001. This hotel is pretty fancy and has a more adult feel. Younger kids may enjoy the other two hotels better (despite persistent attempts to convince our kids to give it a whirl they both enjoy the Disneyland Hotel and Paradise Pier too much to cave.)