I <3 my X200. Also had a T30 for 5 years that was an absolute war-horse.
Thinkpads are built for everyday durability: rollcage in the lid, metal hinges for the screen, drop-sensor for harddrive heads, sealed keyboard, etc.
People always ask me how old my laptop is, even when it was brand new, but Lenovos aren't for looks. The X200 is a hell of a deal, too. It's got a beast of a processor, 4gbs of ram, and something like 8 hours of batt life (real-world) with the extended-battery. Without the battery it weighs 2.95 lbs or something.
I also looked at the X300 which has the SSD harddrive and is the Mac-Air competitor. It's are ultra-light and thin, but doesn't have the same performance and features of the 200 series. The choice is basically light vs. fast (like any laptop).
The biggest complaints I hear about the X200 is screen brightness (or dimness) and lack of a trackpad. I've never liked trackpads, and I love the trackpoint system on Thinkpads, so that's not a big deal for me. I find the screen brightness to be acceptable in 90% of situations, but there are times when it could brighter. Maybe find someone who has one and play around on it to see if the brightness is an issue for you.
My biggest complaint is trying to get the wlan card to play nice under Ubuntu. Windows 7 runs flawlessly on it, though, and I've just given up and installed Ubuntu on VMWare.
Feel free to PM me if you have any questions on the X200.