In my experience from having several Mac's over the past few years, it Applecare is a must. The reason for this is due to the quality of service that Apple has provided.
My first Mac, a 20" iMac, I purchased Applecare. I never had any problems beyond the first year, however I received free phone support for software help that I needed.
Then here is the best part about Applecare, involving my 13" Macbook Pro. I received the 2.53 GHz 2009 version for a Christmas present. A few months after using the system I noticed that the display had some dead pixels and a unnatural curvature. As soon as I noticed this I brought the system into my local Apple Store, they were quick to help and came up with a solution quickly. They ended up replacing the display enclosure since these imperfections weren't normal. About a week later I was called by the store and it was ready to pick up. However, upon arrival to the store to pickup my system I noticed that the display wasn't completely aligned with the bottom case. They understood the issue and said they could re-align the display. About 15 minutes of them being in the back, the Genius comes back empty handed and said that he had some bad news. He says, "It appears that during the alignment process I accidentally dropped your system." I was quite shocked, and after he said that he might have a solution for me. I told him that I can't really go any longer without my system, so he said he would take that into consideration. A few minutes later, he comes out with the manager. He then tells me that a repair would be out of the question and due to the trouble he would simply give me a replacement system. I said ok, then he went to the back and came out with a brand new sealed machine. It turned out that he also gave me the current model that was currently on sale, so I ended up with the 2010 2.66 GHz model. I was very satisfied, Applecare paid itself off.
But wait, the story gets even better. A few months ago, I was using the machine at school. I left my Macbook unattended for a few minutes while I talked to my teacher about something. Since my system was in a backpack, I thought nothing would happen to it. I had used the system 30 minutes before I put it away so it was fine before that. After I finished talking to my teacher I went back to using my system, I noticed there was a huge dent on the left side of the bottom case. I knew Apple would sure not cover me this time around. After I got home from school, I went to the Apple Store and showed them the damage. The Genius was shocked and wondered how that kind of dent was possible. She gave me a one time exception and took it into repair and replaced the display assembly and bottom case. A week later I picked up the system, but I found some problems so I brought it back. The store was not sure what it was this time, so they took it back in. After two weeks they gave me a call and they had sent it to Apple for repair and it was ready for me to pick it up. When I picked it up, the system worked great on first impression. Since they did a clean install of everything, the system was basically like new, around $1500 in repairs had been done by this point. On first startup, I went through the setup and started using it. When I started to use the internet, it would kernel panic, and it did this several times. I brought it back the same day and they ran a hardware test and said the wireless card had failed, even though they had replaced it during the previous repair. I had no idea what the store would do then, so the Genius went to the back and got some information for me. She soon came out with a new sealed machine, I was completely shocked. I ended up receiving a 2011 Macbook Pro 13" with a 2.3 GHz i5 processor.
So after this adventure of the past few years with the Macbook Pro, Applecare has saved me nearly $4000+ in repairs. I am glad I spent the money for Applecare, it has been well worth it.