ThinkPads are probably the best laptops (including Apple laptops) out there. They've got an excellent track record when it comes to durability and reliability and they tend to be very well engineered, efficient machines.
I bought a ThinkPad X61s recently. It was either that or a MacBook Air, and to me the choice was simple:
I could have gotten a MacBook Air. For $1799 I would have gotten a 1.6Ghz CPU, 2GB of RAM that I can't upgrade, a 120GB drive, and a total weight of 3lbs. I also would have gotten a 1 year depot warranty.
With the ThinkPad I could get a 1.6Ghz CPU, 4GB of RAM (user-upgradeable), a 500GB disk (again: user-serviceable), and a total weight of < 3 lbs. I could also tack on a four year warranty, add accidental damage protection *and* upgrade to next-day on-site service. Add in the cost of a used dock via eBay and my total bill came to.... *drumroll* $1600.
Yup. I paid almost $200 less than the MBA, got a machine with better internals, a lighter weight, a 6 hour battery life and four years of unconditional on-site coverage.
To add insult to injury, the X61s idles at about 42C. With both cores fully-loaded I can just barely hit 55C. I don't have an MBA, but I'd be willing to bet that they run a wee bit hotter than that...
Apple makes some nice machines, but when it comes to a subnotebook price/feature comparison they don't really have a prayer against the ThinkPad X series.