Well, I did some more research on how much data I use and found something interesting.
Apparently my iPhone includes WiFi traffic apparently in it's usage. When I went to AT&T's site and looked at the history of data usage, I fit in with the 98%. My highest month over the past 6 months was 1.7 GB, and my average is right at 1GB per month.
After seeing that I feel much better, and am going to proceed with trying the 3G iPad and see how things go. If I find that I'm using it a lot more than I would my iPhone I'll switch to use the 3G just when I really need it or can't get on a Hot Spot. Once I know if I can use the iPad with 3G, then I'll make the decision about canceling my iPhone contract and getting a pre-paid phone.
But (there's always a but) I think that the perception of not having an unlimited data plan is still going to have a HUGE negative effect on iPad and iPhone sales. Unless something changes pretty quick, even this perception that may not be accurate is going to really hurt both Apple and AT&T and the development of future mobile devices and platforms.