I have had the 20 gig harddrive since 2006 (!) and never really felt I needed something bigger. But with all the major uppdates and DLCs to BF3 and all my DLC to ME2 and other games I think it's time to change HDDs.

So I got the old 360 and have finally found a site which sells old HDDS (hard to come by). I understand one need to transfer licenses between consoles, but do I need to do that if I just switch HDDs. I'm unsure if a content transfer cable comes with this particular HDD, so I'll have to download everything (except saves which I can transfer through a memory card), but will I need to transfer licenses? Google does not really give me a good answer.

I do not believe you do because the account is tied to the serial number in some ROM or something... BTW, activate cloud save, then copy all your saves there, then you can copy them back or use cloud... which keeps a copy sync on your harddrive... since I play on 3 xbox's, thats what I have... icloud saves so no matter which one I'm on, there there.

Ok, thanks! Totally forgot about that cloud service

I think Mag is right, I think that's only when going to an entirely new console. IIRC, even then the association can be done through the website.