Some controllers don't support >2TB drives.I would figure whatever you get out ought to work as long as it is the right physical size (2.5 or 3.5). I did use an old 2950 once as a backup 'SAN' using 8x1TB disks in the 2.5" form factor and it worked pretty well.
http://en.community.dell.com/support-forums/servers/f/906/t/19439721.aspx
Depends on the RAID controller. PERC 700 or newer with latest firmware will work.