Network Attached Storage?

[rawfuls]

I know some of you guys are pretty big in computers, so figured this might be worth a try.
Specifically BrianG setup his own media server, so he might know a thing or two, for once.

Need something (no more than 4TB, probably 2-3TB though) that will have a simple interface and easy to use.
Must be able to be networked and then remotely accessed.
Would love it if I could somehow have locked access( so many many users, and some users can access some folders, some can't, etc).

Any ideas?

Budget up to $400.

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What about a drobo?
I'd probably get the $400 model with 2TB drives instead of the 3TBs, and then RAID1.

I wrote up the Drobo FS, as well as the Synology as different options.

Does anybody have any demos of the remote FTP?
I'im trying to make it as user-friendly as possible..

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I'm open to all suggestions, though building a computer dedicated for the NAS duty would be a power hungry heat distributing box, that I don't need in my room.. I have too many of those..
The simplicity of the NAS is that I can grab a switch, hook it up above my shelf, configure it, and then watch as the little lights blink away as I notice people using it.

What worries me the MOST, is the interface that remote users will be confronted with.

In short, I'm after a NAS that will perform Dropbox duties, just... cheaper.