[Nux]

Might be fun to do and the performance is not THAT bad.

Yeah, if you want to watch 100GB Bluray from it will suck arse, but it may be adequate for document storage for example.

Attach a printer to it and you also have a print server. This little setup could serve well an office or a household.

[ginty]

Actually its fine for streaming HD movies too. I have my home server set up from a Pi exactly like this and it is fine. I have mine streaming video via mediatomb and I have never had a hiccup once, even with 1080p video.

Sure maybe transferring files to/from it is not the fastest but I find it perfectly acceptable (say a minute or so to transfer a 300MB file) and as the OP says I don't feel bad about leaving it running 24/7.

Printer serving is one thing I have not been able to transfer from my old server, seems like the Pi is not that well supported for printer drivers, but I do expect that will be resolved soon by people smarter than me.

[npsimons]

Blame the printer drivers on manufacturers; I had an old Brother that "supported Linux" but it really supported Linux/x86. Needless to say, I soon replaced it.