I miss the same things though its not to bad. The biggest things to me are the MMS and using BJIVE for AIM/Yahoo Messenger chat. The lack of data based chat bugs the crap outta me. I hope this is a resolved issue real soon. Im used to being able to chat real time all the time...
I kept my BB Curve along with the iPhone. So far there are a variety of things my BB and do that my iPhone can't, like:
-save and edit attachments
-configure the camera
-push email from my Gmail accounts
-tons of easy to use options
-ability to make TASKS
-ability to schedule items in different time zones
-mass storage mode
-3rd party apps
However, the iPhone is very good for it's initial release and I'm sure it will be getting some updates soon!
I just want the calendar app to be a little more powerful. User-defined alerts, instead of the pre-defined stuff, would be awesome. As would categories and a week view (or just only show the next 7 days in the "list" view).