I've got a 12" Powerbook. I'm looking forward to the rumored new ultra-portables, so I doubt I'll upgrade my current machine internally. I need more space (I want to run Time Machine, too). Thus, the external hard drive becomes my preferred choice. I'm thinking of going the case + drive route. OWC cases look pretty good, but I'm questioning which interface to get. Do you think the slight speed increase of FW800 (which I couldn't use unless I upgrade computers) is worth the money? Is eSATA + USB a better option for future-proofing myself? Are there any hard drive brands to avoid, as a rule? How about buying the "OEM" versus Retail box units? Going a slightly different route, would I be an idiot to buy the WD Passport 250 GB unit that Best Buy has for sale for $150? It's USB only, and I'd really like Firewire, but that price is pretty hard to beat.