I'm getting a new powerbook for school next year and I plan on getting the 15" with 1.67Ghz G4. I'd like to upgrade the HDD to 100Gb but it gets a bit costly even with my $200 student discound. I can save $135 by downgrading the superdrive to a combo drive but I have my reservations about doing so. I don't burn DVD's that much but I'm still having trouble deciding. Anybody have any thoughts?