Leading up to the iPad 2’s announcement, most of us were expecting a relatively modest refresh over the original iPad, and technically speaking, that’s what the iPad 2 is: it’s a slightly thinner, slightly faster iteration on the last generation. It’s amazing, though, how what on paper seems like such a modest spec bump can in fact be such a must-have update for millions of people.

It’s the Apple magic at work, and look no further than the massive volume of original trade-ins that reCommerce companies like Gazelle, eBay and NextWorth are experiencing for proof that the iPad 2 is going to sell like gang busters.

Gazelle, for example, has been swamped with trade-in requests since the iPad’s announcement. In fact, they’ve already paid out over a million dollars to consumers looking to cash-in their iPad and replace it with the iPad 2.

eBay’s Instant Sale program has also seen 7,100 iPads immediately traded-in after the iPad 2 announcement: over one-third of the total iPad trade-ins seen at the site since its debut in October.

Historically, trade-in rates are accurate predictors of a gadget’s sales, and so far, iPad trade-ins are exceeding all expectations of even the experts. If you think everyone and their mother isn’t going to be trying to get their hands on an iPad 2 come next Friday, you’re crazy.

Looking to trade-in your own iPad and want to get the best deal? Here’s a chart on how the services stack up, courtesy of GigaOm.