I’d say: don’t. The performance you will be getting is horrible. Ethernet is connected via USB on the Raspberry Pi, so while via Ethernet, you can achieve about 90 Mbit/s, that speed drops to ≈ 40 Mbit/s once you access a USB hard disk drive. This is without any kind of encryption.
I say, come on, be realistic. This is not a practical thing you're building, it's a fun project that happens to work too.
It's like building a model airplane. You don't do it because you need to fly across the country tomorrow in under 6 hours with drink service and a nap, you do it because you can and it's fun.
What's impractical about it? It's very cheap and easy, and hey, maybe you don't need a faster file server. Hell, some of us with the money and expertise to setup an uber-NAS go with the Pi precisely because it suits our needs just fine.
Why not build it on older, unused hardware, then. It's not going to help to have to go through all the trouble of getting something going on ARM only to have to start over on x86, for example.
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.
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.
That's still better than the 54Mb/s wireless connection (never practically above 20Mb/s) my old laptop that I'm streaming content to has. For the large part, it should work.
It won't be a high performance server, but then, it's a Raspberry Pi.
I'm sure it would be but I think it would teach folks about Samba and mounting drives, it just scratches the surface of Samba but might get someone interested in building a real server with it.
