I've got a 60 gb in my primary mach. which is a dell inspiron b130 (yea it sux) but as soon as i get some $$$$ im getting a macbook pro and running xp pro on it. I also have a 320gb 7200rpm WDE ext. HDD
On my gaming computer I have about 1.5TB (accumulative, it has 3 HD's) with a backup of 500GB. On my desktop, it only has 250GB with a backup of 30GB. On my laptop, it has 60GB and shares both backup HD's. I have 3 externals, each with 200GB. I've used up only about 55% of all of this space but I have reached 90% one time!
I have both an 80 GB that came with the computer as well as a 400GB internal I installed recently. I only partitioned off 300 GBs of it for my windows and I have been using the rest for trying out Ubuntu.
I've got 320gb on my laptop (accumulative), 250gb portable backup, and hopefully I'll be getting a 500gb-1TB stationary backup... My desktop, on the other hand, still has its old 40gig piece of crap, along with an 8 mb slave =D