I sold my 64gb 3G iPad a few months ago for $725 in anticipation of getting the iPad 2 (knowing it was coming soon and would impact resale value). I got the iPad 2 a few weeks ago and after playing with it for a week determined that it was a pointless upgrade for me, in fact I didn't like the feel of the new version. It seems that in order to save weight and make it thinner Apple cut down on the amount of aluminum and consequently it feels flimsy compared to the original iPad. I compared the speed side-by-side with my wife's iPad and determined that the original's speed is just dandy. I also hated how the buttons and dock connector are on the backside rather than the edges.
So....
I put an ad on CraigsList offering to trade my 16gb 3G iPad 2 for the same config in an original model plus they kick in $300 bucks. I ended up doing a trade with a local guy who gave me 2 original iPads in exchange for my iPad 2. One was a 16GB with 3G and one was a 16GB Wifi model. It worked out great because I sold the Wifi version to a friend for $300 and kept the 3G version for myself.
I am a happy camper back with the original iPad