Though it is possible to use a certain other drive on the 360 there really isn't much point as the 360 can take just about any USB drive at any size (As long as you know how to format it i.e use Partition Magic etc (Google it)).

The 360 internal drive is used for -

Movie downloads which self delete so no space required soon as film watched.

Xbox 1 game downloads, the 360 is backward compatible and you can download games from Live BUT you can also pick up most titles very cheap now so again the need for HD space is not needed if you buy the dvd.

Game demos - uses space but how long do you want to keep a demo anyway ?.

Games saves needed space though it could hold countless amounts with a 20 gig drive.

USB drive formatted properly(up to around Two terrabyte) will play your Divx etc movies, mp3s,Photos etc so 20 gig intenally is plenty, use a USB if you want to do movie streaming etc..

As someone who doesn't own the xbox 360 - or any other gaming console for that matter - isn't pretty easy to open up one of these and replace the tiny OEM HDD w/ something bigger much cheaper than the delta price for the "elite" or 60GB versionss of the console?

Jim

Are they still making 20GB drives? Maybe they have just used up all of the available 20 GB drives and are moving up to the current smallest available drive. 

I would not be surprised if the base PS3 went to 80 GB soon.

Quote "price difference between a 60GB and 20GB hard-drive is negligible"

In the real world (read SATA HDD) the price difference between a 60GB and 120GB Hard drive is also negligible.

In fact in the real world 80GB, 120GB, 160GB HDD retail for the same price give or take £1