Tech query

A conversation elsewhere on LJ reminded me that I've been meaning to sort out an external HDD for my laptop (for backup purposes). I had a couple of questions which some of you may be able to assist with...

1) Is there anywhere other than Dabs I can get this kit easily? (Expansys don't seem to do the right things)

2) Is it safe to assume that a USB drive will come with cable attached?

3) If I have a 60GB disk, is it sensible to get 80GB, or should I go for more, in a future-proofing sort of way?

4) I want USB (so I could use it with the PC as well), but is it worth paying for a drive that also has Firewire - can anyone tell me how much the speed difference is in practice from a Powerbook?

Am considering (in price order):
LaCie 80GB USB2 - needs power cable, which is a nuisance; states that it includes cable
Maxtor One-Touch 80GB USB2 - doesn't have specs so no idea about power cable; has this 'one touch' thing where you just hit a button & it Works Magically. Unconvinced it's worth an extra £12, though.
LaCie mobile 60GB USB2 - no power cable needed, easy to cart around.
CrossFire 160GB USB2 & FireWire - doesn't say it needs a power cable, though it might.

All opinion/comment appreciated...

Tech query

A conversation elsewhere on LJ reminded me that I've been meaning to sort out an external HDD for my laptop (for backup purposes). I had a couple of questions which some of you may be able to assist with...

1) Is there anywhere other than Dabs I can get this kit easily? (Expansys don't seem to do the right things)

2) Is it safe to assume that a USB drive will come with cable attached?

3) If I have a 60GB disk, is it sensible to get 80GB, or should I go for more, in a future-proofing sort of way?

4) I want USB (so I could use it with the PC as well), but is it worth paying for a drive that also has Firewire - can anyone tell me how much the speed difference is in practice from a Powerbook?

Am considering (in price order):
LaCie 80GB USB2 - needs power cable, which is a nuisance; states that it includes cable
Maxtor One-Touch 80GB USB2 - doesn't have specs so no idea about power cable; has this 'one touch' thing where you just hit a button & it Works Magically. Unconvinced it's worth an extra £12, though.
LaCie mobile 60GB USB2 - no power cable needed, easy to cart around.
CrossFire 160GB USB2 & FireWire - doesn't say it needs a power cable, though it might.

All opinion/comment appreciated...