looking for advice on upgrading server upgrade.

I am looking to upgrade my server setup as I find it slow when running several task on the server and I'm running out of disk space. The current server is an old Dell optiplex small form factor pc as my server running amahi with a 1 tb and a 2tb usb hard drive. It acts as a file server for 4 Xboxes modified to run xbmc. I run sick beard and couch potato to manage my media and also store photo and document backups.

A few months ago I picked up . Compaq dl580 g2 server as a replacment installed ubuntu server without too much hassle. The problem with this server is that there is only 2 usb 1.0 ports. There is space for another 3 scsi hard drives in the case. Large scsi hard drives are out of my price range.

My question is how should I proceed? Should I fit a usb pci-x card and buy an additional usb hard drive or an esata card and mount the drives in a 4 bay enclosure.

Another option I have considered is to forget the big noisey server and get a few raspberry pis and assign each pi a hard drive and a single task eg one for couch potato one for sick beard, one for torrents.

Any suggestions would be great.