A cheap laptop will do an acceptable job, at an acceptable price. Whatever you buy make sure you get an SSD an get as much RAM as you can afford. And don't underestimate the value of VM's.
Update - I wonder if I could rehouse a MBP in an old thinkpad case/keyboard?
Thinkpad quality is terrible these days, and they got rid of the good keyboard. Just do some forum searches. On the plus side, you can get a used Thinkpad for really cheap - about 1/3rd the price of the equivalent Macbook. Just make sure to get one with a warranty.
I purchased one in December 2012 and I think the build quality is excellent. They did change the keyboard, but not everyone hates it (I think it's just fine and still embodies the spirit/feel of the old keyboards).
I like the MacBook Air more only b/c I have more screen real estate. If the Thinkpad had the same resolution, it would win hands down. NOTE: I have the style thinkpad with the traditional IBM thinkpad keyboard. It. Is. Awesome.
Note: I have Ubuntu running on both. 13.10 daily on thinkpad and 12.04 LTS on MBA. Whichever you choose, I would HIGHLY recommend installing Ubuntu on it.
http://shop.lenovo.com/fi/en/laptops/thinkpad/t-series/t440s...
It all depends on what you want to use it for, and your previous experience. For a Linux user, the Thinkpad will probably be great, although I have heard from people who work at IBM (and therefore only use Thinkpads) that they can be a little unreliable. Macs are pretty good hardware, and with the new MBPs the battery life is amazing.
You can always install Linux on the 'bare hardware', I dislike developing in VMs. But you might find that if you try OS X for a little while you might like it. Not saying you will, many don't, but I find Mac applications tend to have more polish and I spend a lot less time fixing my operating system while I'm on OS X.
Mac is not an option for me, I want Linux-on-hardware.
Try looking for people running your expected hardware with debian online and you'll probably get a better idea.
Unless you don't mind using updated kernels, most thinkpads should work reasonably well.
This should help too: http://www.ubuntu.com/certification/desktop/make/Lenovo/?cat... (Precise is close to wheezy kernel).
I'm in the middle of trying to decide between Lenovo and Apple too.
I personally don't get GPU drivers breaking the computer but I don't use nvidias drivers I use nouveau but I also use Debian so a distro like Arch (which is more prone to packages breaking systems) might be much worse.
I have a w520.
ThinkPad, really good performance, good graphics and battery life.
And if performance is only what you care about (not $) then why don't you take a look at Razor laptops. I know, I know, that's a gaming laptop company, but there laptops are made out of the best and definitely the best laptop I have ever used. Plus they have a snake symbol on the back which is company's logo and which I love as I'm a Python programmer.
I just hope the 13" Haswell retina will allow 16GB Ram.
http://farm8.staticflickr.com/7054/8689948816_4a775858bb_h.j...