Target disk mode is one of those features that you literally only need once every year, maybe even only once every 2 or 3 years, BUT... on those rare occasions when I need it, target disk mode COMPLETELY saves my butt. Like right now. My old powerbook G4's hard drive finally gave up the ghost after 7 and a half years (longest lived hard drive I've ever had). I did have a back up, but it was a couple of months old. If I lost the data I accumulated since that last backup it certainly wouldn't be the end of the world, but I definitely would rather have it than not. So I just plugged a firewire cable into it and connected it to my new computer, and boom, I was able to save all my data. This is why I would never buy a computer that didn't have firewire or lightpeak/thunderbolt or some other port capable of doing target disk mode. Because even though you may only need it once in every 700 days, but on that 700th day it *completely* saves the day.