Thinking about selling 360 and hard drive - how do I erase everything?

Thinking about selling my old 360 and 60GB hard drive for a new 120GB 360 model. I need a new HDD and I think I'd rather just buy a new 120GB model than buy a HDD for $120.

Anyway, I'm paranoid about my personal files and all that. How do I make sure I can erase everything completely so I can sell it without worries? Also, are there anything that's saved on the console itself, like an internal memory perhaps, that I need to erase also?

Thanks!

Oh, and also, can I transfer my save files with the USB? I haven't done this before so just wanted to ask to make sure.

You can transfer your files via USB, that's how I did it. And I just manually went in and deleted everything. Everything, one by one.bluezy