2.554 TB
I have 2x 750GB drives in my main PC. 74GB and 500GB in my media center. And an 80GB in my other PC. Plus a 400GB external drive.
I didn't count my 2nd 500GB drive that I don't have in use.
I have Windows and a broken Vista installed on my 80gb harddrive. Then I have 2x500gb harddrives (one of which I haven't even begun to use yet). Then for backup and transfer purposes to my laptop I have a 500gb external which is basically a backup of my E:\ drive, minus most games.
I have a PC with 2 TV tuner cards and I move those tv shows I record over to my main PC to edit the commercials out and put them on DVD. But I often let them sit there building up before I go through and edit a season's worth.