What Thinkpad should I buy for school?

I need a laptop for going back to school, most likely a nice used one from eBay.

Budget: USD $600

Used for school work, compiling software, Windows XP-era games (my W520 is powerful enough). I will be carrying it around all day. Would prefer a 14 inch machine, and a great display and keyboard.

We will be running me_cleaner (so AMD is off-limits) and Linux.