Depends on lots of things, EST7745. SCSI drives have little to do with whether the box is set up as or considered a server. Likewise, a stand-alone desktop workstation can have a multi-drive RAID array for storage -that does not make it a server by any means. Do you already have the drives? If so, what are they?
If you're going to buy any of this, then give us a better idea of what you're trying to accomplish. Is this going to be in a production environment where it must be available around the clock, or is this just a setup that you want to mess around with SCSI and RAID? Are you more interested in total storage or performance?
The 'generic' answer to your question if you were buying new is Adaptec, but I can think of few cases where it would make sense given the box you'll be using. There's probably a better or at least cheaper alternative.