Sony MDR-7506
They cost about $85, are sturdy, fold up for travel, and sound great. If you have no idea what to get, get these. The rest of the 7500 line of headphones is also good, and the 7502 only costs $50.
Sennheiser HD280
These cost around $99. They have great isolation (I use them for field recording). However, they aren't quite as rugged as the Sonys. Also, they fit very snugly-- try them on to make sure they aren't too tight for you. And if you wear glasses, they may pinch the earpieces a little. Sennheiser in general is a great brand for headphones, and they do have less expensive models.
Had to copy that from an email to a text message :I