I've been using the same Lenovo X200 for four years and have been extremely happy with it. I'm running Linux on it these days after getting tired of dealing with Windows for the first year.
The display resolution has become a drag though (same 1366x768 as the x220). I love the portability and durability of this machine, but I've notice I tend to hack when plugged into an external monitor more over the last year rather than just using the laptop alone.
I've started eye-balling the X230, mainly because you can cram 16GB of ram into it. I would also consider looking at some of the newish T430s/T431s. Better displays, still under 4 lbs.If you buy a Thinkpad new, get the cheapest configuration you can and upgrade the memory (I've used crucial.com) and drop in an ssd yourself - you'll save hundreds of dollars.
I just got my first Thinkpad this summer, a T430s. I absolutely love it, and I'd like to reiterate the approach of buying the cheapest configuration possible and then upgrading components separately.
I replaced the dvd with a bay battery, and I think I get about 7 hours of battery life. I never use it that long at a stretch, and I recharge it every night, so I just always have plenty of battery life.
I run Ubuntu 12.04 at the moment. My only complaint has to do with suspend. I've noticed that while closed and suspended, it still works through the battery's charge. I was surprised to leave it suspended with a mostly full battery one day, and find it off the next day. Also, when I carry it in my backpack in a case while suspended, it comes out of the case hot after a couple hours. Apparently it is still working pretty hard while suspended.
The display resolution has become a drag though (same 1366x768 as the x220). I love the portability and durability of this machine, but I've notice I tend to hack when plugged into an external monitor more over the last year rather than just using the laptop alone.
I've started eye-balling the X230, mainly because you can cram 16GB of ram into it. I would also consider looking at some of the newish T430s/T431s. Better displays, still under 4 lbs.If you buy a Thinkpad new, get the cheapest configuration you can and upgrade the memory (I've used crucial.com) and drop in an ssd yourself - you'll save hundreds of dollars.