Question for audiophiles and tech gurus!?

Okay so i'm looking into buying some new over ear headphones to listen to my ipod. In other words just the 3.5mm jack as opposed to the amp jack. I know some headphones are meant for an amp and therefore i don't want to buy those and not use them optimally. Okay so basically which headphone is the best for listening to 3.5mm devices, is less than $250, and preferably at best buy?