External Hard Drive Advice

I need advice to configure an external hard drive for a new iMac, exclusively for backups. My computer boots from the SSD (Well, will boot - it hasn't arrived yet ). I plan to move the /Users directory to the 1TB internal hard drive. (I am fairly knowledgeable of Linux but a new Mac user - but have read numerous threads and believe this move makes sense).

My question is - does the following make sense:

2 TB Iomega Firewire 800 external drive (I know thunderbolt devices are coming but the initial ones are bound to have a price premium).

On this drive, one 256Gb partition for a clone of the SSD. The remaining space used as a partition exclusively for Time Machine.

The computer will be used by my wife and I just want her to have the assurance she can recover past documents for any reasonable period of time - plus be able to restore the boot drive easily in the event of a disaster.

the partition part seems to make sense to me. Your computer will have 2 internal drives? An SSD and a 1TB?

That should work nicely. If you are going to do that and are consistent with updating the clone, you can probably safely tell Time Machine not to back up the Applications and System files. Thus leaving a longer period of time for data backups before the other partition fills up.