Look at how plump the Western Digital My Book Pro has gotten, now at 1TB. It's now called the My Book Pro Edition II, and still looks like a book, but now more like a fat dictionary. Best of all, it holds twice the stuff, but isn't quite twice as expensive.
When we reported on the similar My Book Pro 500GB model with FireWire 400, 800 and USB just three months ago, it was $350, now here's the twice-as-big 1TB version retailing for $549. Plus, the RAID-striped drives inside make for fast response and transfers.