The other cool thought I had is if you happen to be flying and chose to pay to have your, say iPad on the in flight wireless you will be able to continue texting people on the ground which is a HUGE advantage over the system now, especially if text messaging is a significant portion of how you conduct business.
club. Honestly, I was leaning that way anyway as I have an iMac, iPad2 and iPod Touch, but iMessage sealed the deal.