Is this gal asking for too much!? Lol. I wish I could get a iPhone for tmo. Nothing against my MyTouch but I love my iPod touch and wish it was my phone. I know you can do the whole jailbreak thing but haven't heard many good stories about that.
I've got a jailbroken iPhone 3G and haven't had any problem other than my app folders blowing up one day and having to re-construct them. Just know that all firmware may have a jailbreak but not necessarily an unlock.