Just don't go to a store where you can fondle them both. You will leave with an iPad 2.
Personally, I own an original iPad and when I checked out the iPad 2 in the stores, I was unimpressed. Sure, if you're buying a new one, go for the latest technology, but it was certainly not something that would compel me to sell mine in order to upgrade.
It didn't really feel noticably lighter in my hands. It did feel noticably thinner, but almost too thin... the lock, power and volume switches have to be mounted at an angle in order to accomodate the wedge shape, and I find that annoying compared to my existing unit.
But you know what would make me hesitate from buying it? I'd have to look for a case instead of a silly smart cover. I really like the original black Apple iPad case with the flip cover. If they would only sell that exact case for the iPad 2...
I might jump to the iPad 3 whenever it comes out.