I think that if you're looking for the safest option and don't mind spending a bit of money for that security, then a self powered external RAID 1 (It's called Mirroring) is a good option. I have a
similar external and it's been working great. Fast speeds with the FW800 (it even has eSATA and USB2.0).
These are very easy to set up. If you get the OWC version, I think you can choose the mirrored version and it's already set up for you. Ie, 2TB of space = 1TB because the data is written to both drives at the same time, so if one fails, the other one still has a mirrored image of it and is accessible.
RAIDs are fairly common and it's not only for sophisticated users.
If you don't want to spend the money, then these WD Passports are fine. You can grab one that's on sale. FW800 versions are usually harder to find and a bit more expensive. If you get one of these, just keep backups of your important files and you'll be fine. Many people use single drives without issues.
You could get
this and pop in your own 1TB 2.5" Drive that you can find on sale. It's fairly easy nowadays.
Many people use the G-Raid drives, but I keep hearing horror stories about them.
Final note:
It seems like you just want to backup your MBP (via TimeMachine?) then just get a USB2.0 drive that's on sale. They're self powered. The WD Passports are a good solution. Since you just want to keep a backup of your MBP, I am fairly certain you won't be lugging that drive around so you will always have 2 copies of your data (One on MBP and one on your external). So no worries, loads of people do that
First time machine backup will take a while so you can leave it overnight...then subsequent backups will be faster. USB 2.0 is fine for that.
