best affordable storage solution?

I am purchasing a new Mac and am researching a storage solution.

I usually work on a rented Nitris for feature films, hooked up to an Isis.  I would like a home set-up.

I will probably purchase a MBP w/retina 15" top of the line with the NVIDIA 2GB card.

I have media on old FW 800 drives, Digital 8/Hi-8, Beta SP and am thinking I would like to edit in uncompressed SD and upres at the end.  I would like to have my material properly backed up and/or redundant with a RAID.

Any suggestions for what would be a reliable and affordable set-up for storage?

Using the Avid media calculator, looks like I might need about 3TB, but would like to have plenty of extra room for concurrent other projects, so maybe 5-8TB?

Thanks in advance for your input!

Best,

Ceci