We've got a load of Lenovos here at my house, and I'll be looking at a new one at some point within the next year. That being said, if you're going to be traveling a bit, I'd go for the ThinkPad line. The Edge line might work as well, but traditionally the ThinkPad laptops have been aimed at professionals (ie: business people) who are on the go quite a bit. My ThinkPad is ~5 years old at this point and still going strong, and doesn't show any excessive wear from going in and out of a backpack every day.
The IdeaPads are generally fine, but they're targeted at consumers. They're not as rugged, and often aren't nearly as customizable as the ThinkPads. I know there are usually decent discounts on
Barnes and Noble's Lenovo portal, and often that is the site to go to if you're buying from Lenovo directly. They've had a ton of deals on many laptops with the last-gen Sandy Bridge architecture, and are even starting to give discounts for the Ivy Bridge based laptops as well. Generally the advice is to upgrade the processor from the i3 to the i5 (~$30), add the 1600x900 screen (~$50), and perhaps go for a 2-year warranty (~$90). The HDD/SSD + RAM are easily accessible, so don't bother paying the stupid prices they charge for that.
If you're willing to spend the $1100 (student discount) for the 13" MBA, I'd look in the $700-900 range for the T400 series (14" screen) or the X-series (11-12.5" screens) that are geared toward portability. Personally, I'll be looking at the T430/T430s which is the latest Ivy Bridge based version, then adding the nicer screen, fingerprint reader + that pointing-nub, and considering the $50 upgrade for the dedicated graphics as well. Given Optimus, it'll likely be a worthwhile upgrade for performance, without sacrificing battery life. And if you're going to the $800-900 level, you can definitely deck out the laptop + get extra RAM from NewEgg.