I was in your exact situation about 6 months ago. Couldn't keep those damn stock Apple 'phones in my ears more than 5 minutes before the pain outweighed the music, which itself added to the pain as the sound quality was awful (goes without saying). After doing a little research the Sennheiser CX500 seemed to get good reviews, and after finding them online at B&H Photo for 60 bucks I took the plunge. I haven't compared them to anything else, but I can keep these things in my ears for hours with no discomfort and the sound is nicely balanced and refined. A huge step up from the stock iPod headphones in every way. They also have a neat little slider volume control on the cord that sometimes comes in handy when it's not convenient to grab the iPod and work the wheel.
Best of luck.
Best of luck.