OK, I've had my 13.3 Macbook since April 2008 and the only device connected to it is a Ruckus broadband gateway to access the internet via ethernet. I know, yawn. Currently have Mac OS X 10.5.7 and decided I gotta download Windows 7 RC (because I can) but want to get an external hard drive to back up my laptop first. HD = 250 GB. Has a firewire 400 port For an external HD, I considered WD My Passport Essential 500 Gb, but after reading through the forums, it sounds like the USB connection will a. slow everything down/ suck too much power? b. Is getting an external hard drive with firewire preferable, critical? c. How important is having a hard drive with it's own power source? Will initially use Time Machine Portability is NOT a factor Not-networked, not a gamer, will be working from home a lot more (OS X & Windows) Plan on using bootcamp till I find a need for Parallels, vm fusion Will be downloading maps, geocaching stuff Any advice on most critical features, not necessarily specific brand names for an external HD to back up a laptop?