File Management -Hard/Software

Quick question, what do you use or have heard/experience (in an enterprise environment) that is a great file management software/hardware?

I would be interested in a hardware solution that can hold 2-3Terabytes of data and be able to manage Active Directory users permissions effectively and efficiently.

Any recommendations?

Hardware:
Dell, HP, IBM etc???

Software:
Just use windows active directory to manage user security or is there some other cool software?

Thanks.:thumbsup: