I'm getting an iPhone next month. My upgrade gets me a 50% discount on one instead of being applied to the whole amount (which is super cheesy if you ask me, like AT&T hasn't been getting loads of money from me for years). I need a new mp3 player as well as a new phone since they have both developed battery charging issues among other things & even if I have to pay $100 it just makes more sense to get one device rather than 2 and I'd have to pay at least $100 toward the mp3 player.
Plus I'm looking forward to being able to say "Oh I have an app for that!"