I have a chance to buy a Western Digital My Book Essential 500 GB manufacturer refurbished external hard drive for $70. I want to backup my 622's recorded programming. Don't have a lot saved but some can't be replaced. I already use a My Book with my PC so I know it has its own AC power pack and is USB 2.0. Any reason this drive won't work with my 622? What about with the newest receivers? I'll have to upgrade someday. Also, approximately how much disk space does 1 hour of HD programming take? Thanks.