Hm, 3.0 fixes my biggest pet peeves. They previously would have been:
1) copy/paste
2) Text issues (deleting single texts, forwarding texts - does 3.0 allow you to forward texts?), and obviously MMS
3) Push notifications
I was never really too concerned about Push e-mail, yes it would be nice, but I can live w/ out it. I more want notifications for my IM and apps like Tweetie, so that'll be nice.
My new ones would probably be:
1) video not supported on iPhone 3G with 3.0?
2) I guess battery? i never really have an issue w/ the battery, i have a car charger and I charge my phone every night. I don't really understand why people complain about having to charge it every night. I don't think it's that hard to just plug in a phone. If you're out of town, fine, buy a car charger.