Please suggest NAS device

Hi

Please suggest me a good NAS box with RAID support (mirroring) and web access to it using HTTP/FTP. I just realized I have a lot of data what I can't lose. I already have 320Gb external HDD I am using as backup, but need something more.

Thanks!

UPD: I was thinking about buying NAS without drives, and buy drives separately. May be DLink is good option?

UPD2: I need NAS for home. Probably 2-bay device.