I want to take all my music, movies, etc., off the laptop I've been using for the past year or two and throw it all on a headless P3 box running Debian or Ubuntu, so I can get to all my stuff from any of my computers. If it's going to leave my laptop, I'd also need to setup a VPN so I could get to it all when I'm not at home.

What would be the best way to go about this? I could probably do it through an SSH tunnel, but I'm not sure how it would hold up from streaming music and movies from hundreds of miles away. This'll also be a torrent box, so I need some way of managing that remotely as well.

I need to get to this from other linux boxes, OS X, and possibly Windows

I don't think that any networking solution solves the first problem - there is no way to guarantee sufficient bandwidth between your laptop and your server once your laptop goes off your own network. You can use rsync on any Linux or OS X box across SSH, so it's trivial to sync files between your laptop and a second set on your server, and run a DAAP service on your server to make the server copy available to other clients on your network.

For the second question... The last time I needed to do this I connected to a server over SSH, ran "screen" to setup a persistent session and launched the command-line BT client (bt-headless.py ?) inside the screen session. There's a Web interface called Clutch for the Transmission BT client, but I haven't used either Transmission or Clutch yet myself.

Yeah, that's what I was afraid of. What if I ignored video and only wanted to stream audio remotely?

Clutch sounds awesome. I've had my laptop running for around a week now, nonstop downloading. Don't think laptop HDDs were really meant to be spun up that long...

You have the same issue, really. Most protocols mainly involve moving text around, so work reasonably well even on a small amount of bandwidth, and you can cope with slight delays loading Web pages anyway. All multimedia involves massively larger quantities of data, and interruptions in the flow are really annoying. The same issue applies whether you use a big public site like YouTube, or your own server.

Again, you can make a big set of media files accessible to anything on your own LAN with a DAAP service, so it's just a case of keeping any other copy in sync, and rsync is a really convenient way to keep two copies of a fileset the same. For DAAP, Firefly was pretty easy to setup and didn't need any other services, IIRC.