Best Portable External Hard Drives Reviews

My Passport Essential SE 1 TB USB 3.0/2.0 Ultra Portable External Hard Drive (Black) is compatible with both PC and Mac – I have a Mac Book Pro, a desktop (Window XP) and a laptop (Window Vista), and I am planning on getting a new laptop which is going to run on Window 7. Can this HD back up all the data from all these computers simultaneously? Or do I need to format it every time when I hook it up with different laptops?

I am planning to buy this disk, but…
I´m a little bit confused about “Dual USB 3.0 and USB 2.0 compatibility”

Is the USB 3.0 connector phisically different than the USB 2.0?
Does this drive have ONLY one connector? which one?
I only have USB 2.0 connectors in my PC and my Mac. Will I need some converter if I buy this disk?

I believe you would have to re format it for the Mac. So you really need two seperate drives. Below is from the specs of the drive.

Compatibility
Formatted NTFS
Windows® XP, Windows Vista®, Windows 7
Mac OS® X Leopard®, Snow Leopard™ (requires reformatting and will work in USB 2.- mode)

I have a Windows PC and a Mac Book Pro.
I have a 60GB USB external drive, formatted NTFS.
I ONLY use it as a file storage, mainly videos which I download with the PC and edit in the Mac.
The Mac reads it perfectly, so I think that as log as you don´t need to run Mac applications, the NTFS formatted disk should work Ok with the Mac.

USB 3.0 means more data transfer speed. If you have a newer laptop, that means you have USB 3.0. Anyways, USB 3.0 is backwards compatible with USB 2.0