Should I build a file server if i only have one system?

Title is sort of lieing but i only use one of my sytem's. I went into my attic and discovered a old athlon 64 x2 PC and thought about a file server but would it be a waste of money with the one system that i use.

 

If you think i shouldn't use it for a file server what about a game server? Any suggestions?

File servers are always useful. Not only could you store files that you don't need on your main machine, but dont want to get rid of, you could also make backups to it.

As a game server I dont know how good it would be considering how old the processor is. For hosting a few people I guess it would be okay (providing you have the bandwidth of course)

I don't think that it would be of much use as a file server. Maybe if you want to be able to access files from your wifi (bluray players can do that, or maybe a handheld device or whatever), but since you really only have on system, I just don't see the point. Now, if you ran out of sata ports, then there would be a good reason to have a file server. Other than that, I just don't see a good reason why aside from redundancy in a good raid set up, which would harck a lack of sata ports, or a raidz set up.