Well, I was sorta joking, but thinking more about it, I think it's a good idea ;P
So, here we go; inspired by Trace's 4GHz Club, I hereby announce the formation of the (unofficial but awesome) TBCS 5TB club.
Post your storage stats (screenshot/df output/etc) and an explanation of how you're doing it.
1) Value must be must be unique, usable storage space.
---If you are using a RAID5 or 6 array, your parity drive does not count toward the total. If you are using a RAID1 or similar, your mirror drives do not count toward the total. If you are using WHS's 'duplication' feature, the 'duplication' space does not count toward the total since it is essentially acting as a logical mirror drive.
2) All storage must be accessible as a single unit.
---This may be multiple individual drives on a single system, an array of drives on a single system, multiple drives on multiple systems that can all be mapped to one, etc. As long as all storage is accessible at one time from a single system, it counts.
3) You must post an explanation of what makes up the space and how you have it managed, and a screenshot or command output showing the volume (see my first post for an example).