The precocious lads at Xbox 360 Fanboy have confirmed with multiple Gamestop managers that the trade-in value for both SKUs of Microsoft's console has increased. You will now receive $250 for Premium, $200 for Core (about 67% its original value) and $50 for the original Xbox.
Obviously, the financial upgrade coincides with the impending US release of the $479.99 Elite model on April 29. Trading in an Xbox 360 Premium and picking up an Elite will leave you with a net cost of $230. Being that the 120GB HDD costs $180 separately, you're paying an additional $50 for the black paint job, HDMI output, and HDMI cable. But will we get a chance to transfer our save files in-store? Doubtful. (You can still play full titles, if you re-download them, via your Gamertag without having to pay again.)
The Gamestop managers said that the money does not have to go toward the Elite. So whether you plan on upgrading or looking to bid farewell to the console altogether, now is likely the best time to go the Gamestop route.