Answering my own question, as it combines a few elements from Omar's answer and James Sutherland's comment and a few others. Thanks for everyone's help!
As I said in the question, I already transferred all DRM rights to the new console in advance using the online content license transfer tool.
I concluded that re-downloading over the internet 593 items in full (over 60gb) takes absurdly long. I'm cheap, but I ain't that cheap. I went ahead and picked up the $20 Xbox Data Transfer cable from a local EBGames (they stock them).
- This pulled across ALL data on the older Xbox hard drive to the new Xbox hard drive in about an hour, though I was getting some intermittent read errors and had to retry a bit
- it also pulled across my old savegames and settings, which I wouldn't get from a straight download, so that is a nice perk
Once you've done that, as James Sutherland correctly pointed out, you STILL won't be able to play this content unless you are logged in to your Xbox Live account. To get the content playable for anyone on that Xbox -- regardless of whether they are logged into Xbox Live as you or not -- you must re-download each and every bit of your DLC.
There is something magical about this re-downlad where it "tags" the DLC that was copied from your Old Xbox as belonging to the New Xbox. Once you do this, you can play the DLC without being logged into Xbox Live. I personally confirmed this!
Now, to re-download everything is a pain in the butt, but there is some good news --
- since the content is already there, copied across via the Xbox Data Transfer Cable earlier, the downloads are very fast, basically just verification of the downloaded file and writing the "magic DLC bits" to the disk
- your Xbox Live Download History makes it fairly fast to do this; just go down the list and click the entries, but don't go too fast, as there is a maximum of 25 entries in your download queue.
The Xbox picks this queue up dynamically, and it is MUCH MUCH faster to do it through the web UI than it is with the controller. Watch near the top of the page as it will update dynamically after you click to confirm that the item was added to the queue. This takes a few seconds, so don't go too fast.
Anyway, once I've walked the list of 30 pages, everything will be "as it was" on my old Xbox. Finally. :P
The cheapest option is definitely going to be the USB route as mentioned by others.
Ignoring the fact that Microsoft's hardware prices are inflated and overpriced, if you go strictly off a cost per GB, then buying the console with the 250GB drive is your best bet for the money. Using the averages prices these days
GB Total $ $ per GB
250 $100.00 $0.40 (w/console)
250 $130.00 $0.52 (standalone drive)
120 $100.00 $0.83 (standalone drive)
60 $70.00 $1.17 (standalone drive)
16 $20.00 $1.25 (USB Drive)
I would assume the standalone drives have a warranty of their own, and the one with the console would be part of the console warranty, but I'm not sure on those.
Best Answer
That should be fine, but there is a drawback.
Content on an Xbox 360 has two licenses: Device and User.
The User ID is simple. It matches your Xbox Live account, and allows your user to play saves and content assigned to that user.
The Device ID is more complicated. This ID matches whatever Device (aka console) the content was originally purchased on. Save games are not a concern here, only purchases. If the Device ID of a purchase matches the console, then any user on the console can access that content. However if the Device ID is different, then only the original user can play the content as long as they are signed into Xbox Live. Even if you deleted and re-downloaded the content, it will still use the Device ID of whatever console first downloaded the content.
To get around this, you will need to perform a License Transfer on the new console. You can only do this once every 4 months. From the DRM FAQ
This should get you set. As long as you follow these instructions to transfer the licensing, there shouldn't be any further issues.
Do note that the original model Xbox 360 uses a different kind of HDD. If you did get one, it wouldn't be compatible. Since you mentioned you will be getting a different model, this shouldn't apply, but I included it for completeness.