Just how I play it:
You get one year with the OEM warranty. In my experience, it's more likely to be defective early one. If I get through the first year with no issues, then I rather assume I got a "good one" and I use it for another 6-12 months. Then I sell.
At this point, I have gotten ~2 years out of the laptop, saved $250 by skipping Apple Care and get ok resale value, especially when you realize you never spent the $250.
Of course, if you are going to keep the laptop for a long time, then maybe it's more worth this. After 2 years, I usually want a new one.
Some people will say they are easier to sell with Apple Care. I've never had a problem. People care about price and I would have to raise the price if it had 1-2 years of Apple Care left.
I figure I stay in a pretty current laptop for about $50 a month this way, and I'm ok with that.