1) Tape drives
We currently have a 200Gb tape (uncompressed) at work, you can also use many tape drives and get robotic libraries to automatically change tape. Again, the idea is to back up terrabytes without needing someone to sit there and change disks.
2) Heat management
Heat disipation is pretty much equal to power requirements. Our new servers need 700W + tape + monitor, close enough 1000W. How much of an issue it is with one server, well that depends where you put it. Again, at work we have a room with 4 servers, couple switches, couple PCs. To cover that and allow for expansion we just fitted a 7kW AC unit.
Probably AC won't be needed for a single server, but heat disipation is always a problem.
Definately worth considering getting a decent chassis and minimal components, gives you more chance to upgrade up to 6 or even 8 drives for example.