Am I doing something wrong, or do 1st generation iPhones require particular headphones? My white iPod headphones work, but most of my other ones wont fit? Is the standard solution to purchase an adapter?
Do you have an original (aluminum backed) iPhone? If so then yes, unfortunately Apple recessed the headphone jack and you do need an extender. If you have an iPhone 3G, 3GS, or 4, then you shouldn't need to, as the headphone jack is flush with the device.