Navi (from the computers in Lain) is a used 1U rack-mounted server, with an 800MHz Pentium III and a 10gb IDE hard drive. She currently has only 128mb of SDRAM, but I'll be upgrading that to 256 or 384. She has no room for a CD drive, so I'll just have to back up everything across the network to my own PC.
You can see the seller's page about her here, although if she's one-of-a-kind that page may go down soon.
It will take at least three weeks to get our new DSL online; I'll be using that time to install Debian and configure her.