Back up over the Net to another system, or use tape. If you're building your own box, you should be qualified to build a new kernel if you have to update the Ethernet driver. Power Supply, Case, Cooling Whatever you do, don't buy the latest hot CPU and drives and then mount them in a case with inadequate cooling, or hook them up to a flaky power supply that's going to blow out and fry everything. That's not good. If you live on the bleeding edge, hardware-wise, then your case, power supply and fans will outlast several motherboards and CPUs.
Some people take the motherboard and CPU from what was a hot desktop box and use it in a web server.
Again, think about being able to shuffle the components you buy today into another machine next year. Mike chooses PC Power and Cooling power supplies, with Sparkle Power as a second choice. Choose a case with plenty of room to work inside, a side panel that's easy to remove, and several places to install fans. That means he needs a tower case with a lot of cooling capacity, and he recommends Supermicro. They make a tower case with mounting points for fans in all the standard places, as well as blowing sideways across the drives.