Umm... songs as ringers work fine, plus it would use a different speaker (loud external) and mute your headphones if you were listening to music.
I've used mp3 ringers on my Palm phones that I've made myself since like... 2003. I like being able to make them myself and not have to pay a fee for them when really I already "lease" the copyrighted material for myself, and the ringers are just for me on MY phone. Charging for ringtones has always seemed a ridiculous and unnecessary glut of profits and I refuse to buy them.
If there is no even 3rd party hacked way to put your own music ringers on the iPhone from music you own, I will be PISSED. That could almost be a dealbreaker because it would make me so angry. But I know Apple wants profits and blabla... so I'd probably get an iPhone anyway and just wait it out or deal with the defaults, and maybe buy one special ringer for the hubby.
But still, I'd be angry having to pay for it.