Apple care is actually pretty dodgy. The average end user wouldn't see it, but if the problems my friend who worked as a certified apple tech, for an apple store are any indication - its not awesome.
Not directly related to the care, but to give you some idea of how their service works (at least in Australia): In many cases they had to take logic boards and other components from DOA machines to replace parts because Apple wouldn't authorise a replacement.
A good example is they will not authorise more than one replacement part for a machine within a period of a week. Yet they knowingly sold logic boards with dry solder joints for some months (forget which machine this is, but I think it was the eMac from 2 years ago, possibly the powerbook). The average failure rate was pretty high, but not high enough to do a recall. It wasn't uncommon for this problem to show up in conjunction with other problems and thus the fights with apple service started.
Its just lucky for a lot of users that apple ships quite a few DOA machines or they wouldn't have been fixed in anything like reasonable time. The secret is in a term called "stitching", because every apple has a serial number, the DOA machines would have the part salvaged, they would claim that the part was from a legit machine get a replacement sent out and install it. Because the serial came from another machine it wouldn't alert apple service.
Apple hardware is great and all, but only if you don't get a dud.
[edit]
and until now I took it as a given that I should buy the care with it.
You should still buy apple care! Despite apples issues, you do have a contract with them that they have to honor with regards to the warranty on your machine. The other think my friend pointed out is that he was doing 85-90 service jobs a month, and a large portion of those occured within months of the warranty expiring. This did not include jobs that were not completed because the cost was prohibitive. He used to get at least a dozen a week were the cost of replacement for a logic board was about the same as a new eMac (probably the mac mini these days) - and thus the customer would forgoe the repair and buy a new machine.
Don't do without it - it will bite you. Just be aware of your rights, read your contract and make sure you don't ding your machine. That will be the first thing they jump on as the cause!
