By request, here's some more detail about why ThinkPads are uniquely qualified as tools for typing, which is what coders mostly do. I started ThinkPads with a 765, went through a couple of A30s and T2x and T4x models, today I use a T61p, and I am drooling over the T510, so I am walking this walk.
First, there is nothing better than the TrackPoint (a.k.a. nipplemouse among other things). I can't abide trackpads; I always disable them on UltraNav keyboards. Trackpads are too easy to touch by accident, especially when using your palms to stabilize the computer that is both topheavy and highly valuable. Trackpads also take your fingers away from the home row. I do see why some people dislike nipplemice - the right index finger can get overworked, and making big, fast, precision movement such as for artwork is harder. But I'm no artist.
As nice as TrackPoints are, the real killer feature of ThinkPad keyboards is their key travel and resistance profile. ThinkPad keyboards have long key travel compared to other laptops (this is Apple's major sin), nice key shapes, nice arrangement, and a nice resistance profile - keys start a little hard to push down, but finish easy. Tastes vary, I grant you, but if you've only ever used short-travel keys you don't know what you're missing.
Even within the ThinkPad brand, quality varies by keyboard OEM. NMB, Chicony, and Alps all make keyboards for the T6x series, for example. Google those names and discover a subcommunity of keyboard fanatics. Note that you have to buy by FRU, not part number. I will follow up with the FRU I use; I don't want to mislead readers by trusting my somewhat confused notes, so I have to take my laptop apart to be sure.
If your coding task absolutely requires a Mac, the plastic Macbook is less bad than the others. Something about the shape of the case in front of the keyboard makes the keys' short travel less annoying, and the plastic is much better at grabbing the heel of the hand than brushed aluminum (shudder). It is still definitely out of ThinkPad's class, though.
I should also mention that Toshiba makes/made a black shiny keyboard for some of its models (e.g. Satellite A300) that has very nice travel and resistance qualities as well. But then you're stuck with a trackbad. (That's a typo, but it was so appropriate I left it in.)
PS: Beware early T4xx and T5xx models. Lenovo experimented with replacing the strong aluminum keyboard baseplate with a glued aluminum and plastic base that was shot full of holes to save weight. It didn't work well. The corner keys suffered really annoying flexing.
