Microsoft does two checks to make sure your stuff you purchased on the Market Place is being played by you. Anytime you get a new X-Box, you need to transfer the licenses. Unfortunately, this can only be done once a year.
The first check is your gamertag. Of course, when you purchase something, it's tied to your gamertag. This is verified when you log on Live. If you can't login into Live, the next check is the console itself. If your purchased the content with the current X-Box, it will allow you to access the content. If you purchased from another console, you won't be able to access it offline.
You have to actually do this on their website. I just wanted to throw that out there in case someone didn't know.
You only have to do this if you are transferring data to a new console. If you are simply upgrading to a larger drive, you don't need to transfer the licenses. The licenses are attached to the console, not the drive.
Hmm... I once transfered (not with this cord...) data from an old 20GB 360 to a 60GB HDD and a new 360 (still the older white model, then the end of that SAME year the black one came out ARGH! - anyway) and I was using an official MS 360 USB memory card, the older system wouldn't accept any other memory USB card. And due to memory constraint of the USB card I was unable to move my FF XI and PSU data to the knew console... but everything else moved over. The only game I ever had an issue with was the original Gensis Sonic the Hedgehog download game. it was there, but it's only a demo. I've deleted it, and redownloaded it, but it's still only a demo. My Achievement Points are showing for Sonic, but I cannot play the full game anymore. Yet all my other games are perfectly fine (other than all the games I've gotten that are just not downloads anymore....) Double Dragon, Outrun 2 Online, Gauntlet, Joust, TMNT 1989,... Double Dragon is the only one affected that was turned into a "demo" whether I'm online or not.