Here's a few tips on buying Apple gear and credit card extended warranties. The bottom line is:

• Consider buying AppleCare with American Express or certain other cards, like those from Citibank, to get an extended warranty that extends 12 months past AppleCare's 3 years. That's 4 years total!
• If you don't need AppleCare, then try to buy with American Express, or some other card that will still get an extra 12 months. Check the card details to see if they offer a warranty extension.
• Consider skipping AppleCare with a card that already has a warranty extension and doesn't go beyond the 3 years of Applecare. You would get 24 months of basic coverage (one year original plus one year card warranty). For the price of AppleCare, you get only an extra 12 months, although some will want the telephone question coverage of AppleCare.

Buying Tips

Buy products when they just come out, or wait until the next version comes out. It seems like Apple products don't really go on sale, so you might as well get the newest stuff, or wait if you can. A good place to check is MacRumors Buyers Guide. That being said, if you need something, then you need it, so just buy it. If you're not sure, then you can probably wait.

AppleCare

In general, you'd probably be off without extended warranties unless there's something special about your situation that suggest one is worth it. Plus, if you buy with the right credit card, you'll get one year extension, giving you a full years without paying a cent. Here's an article on LifeHacker: Skip the Extended Warranty; Use a Good Credit Card Instead. I live on the beach, so everything tends to rust, so I tend to buy extended warranties for this reason.

American Express or double-check before you buy AppleCare

Both American Express and Mastercard offer warranty extensions of up to one year for using their cards. However, there's a huge difference in their policies. American Express specifically states that they extend past supplemental warranty extensions like AppleCare. . I quoted the details below. American Express will provide up to one year additional for warranties up to 5 years. MasterCard only goes to one year. Visa goes to 3 years.

References

Here's a good article with more details on why you should American Express for all extended warranties: 2012 Credit Card Extended Warranty Study.

These articles maybe too old:

• Another comparison, from the NYT: Credit Cards With the Best Extended Warranties
• LifeHacker: Are Extended Warranties Worth It?