Tom,
I'm not sure if running your own server rather than using a hosting service will be the greatest of ideas.
Currently, treeweasel.com is itself hosted under genetikayos.com, which is on a machine owned by an ex-co-worker and is co-located at a hosting facility. According to this friend of mine, QS's bandwidth needs are a drop in the bucket compared to all of the other (mainly open sourcE) projects he hosts on the system. This is why he's been perfectly happy to host it, and why visitors fetching files off of treeweasel for the past two years have enjoyed fast file downloads with no queues or download limits.
If you run your own server, you'll end up providing service similar to what I /used/ to have before shifting those files to the genetikayos system... where visitors were limited to downloading one song at a time, and at slower rates. Back then, I had a 128k upstream limit on an ADSL connection.
Speaking of which, I haven't seen you reply whether you're getting ADSL or SDSL. As mentioned before, with ADSL, your upload rate would be slower than your download rate, and with SDSL, they would be the same. When you're hosting content over your own local connection, your upload rate is everyone else's download speed. Contrast that to a hosting service, which usually provides 1.5Mbps service or better (3x the 512k service, or 6x the 256k service) and may even "burst" to higher speeds.
With my old 128k upstream service, I found I was able to provide adequate service to roughly 2 visitors simultaneously (with "56k" modems)... and also at that point, my service was degraded to where it was unusable for myself. So, I took advantage of some of the Apache webserver's configuration options to limit bandwidth to one file per person, and a total upstream limit of about 100k so I had a little room left for myself to download and upload things. At times, I still had as many as 4 people trying to download files. When you post a new file, you'll see a surge of activity as people want to hear it. It can be very taxing on a personal DSL connection.
With 256k upstream, you could handle 4 users at 56k; with 512k, 8 users. But bear in mind that many users of your website these days also will have their own DSL or cable connections, and they'll suck you dry of your full bandwidth per connection (with a click, I can pull 512k/s from you from my own home DSL connection) ... because again, your upload speed is my download speed, and most ADSL and cable connections provide around 1.5Mbps down (just not up). And while I'm sucking down that full 512k/s, I'm going to be thinking even so, "This is much slower than it used to be" if I'm used to downloading from your hosting service which would happily provide me the file at full speed. It'll take me 3 times as long to download the file.
I just want you to be aware of all this, for as you know that your site's popularity is still growing, not shrinking, and moving your hosting to a machine on your own property could be a step backward. A better solution would be to rent your own U1 at a hosting service similar to how you're doing things now... you can even buy your own U1 rack system so it really is your property, but by putting it into a data center with a nice "fat pipe" the quality of service to your visitors will be much higher.
Linux, BSD, etc...Next subject: Both are good. BSD is perceived by many to be more stable than Linux in terms of being bug-free, less prone to security attacks, etc; it relates back to the core philosophy of BSD, whereas Linux distributions tend to be more "cutting edge". Also, as Linux is more popular, there are more hacks for it (in fact, it is Windows' own popularity that is its own downfall - it is attacked not merely because it is so insecure, but because it is so prevalent and run by "average folk" that it is easier to find a vulnerable Windows system than a MacOS or Linux system). Stability and reliability come at a certain cost though - BSD may not run on the most cutting edge hardware because drivers may not be available. It is "slow" waiting between releases of the BSD operating systems.
Within Linux, the different distributions also show a degree of variation in their cutting-edgedness versus security-mindedness as well. I would personally recommend avoiding Red Hat's free version, Fedora, because it is really Red Hat's "testing sandbox" - running Fedora is like testing a beta for them. Fedora is where Red Hat tests out unproven software that they may later roll into their commercial Enterprise releases. Fedora Core 2 was an unpleasant mess, and while version 3 which recently came out has received better reviews, I was soured by my experience with version 2.
On top of that, I never liked that in order to upgrade Red Hat to a new release, you have to "take the system down" and boot the next release's CD. There's no "live upgrading."
My home system now runs a variant of Debian, which is more security focused than Red Hat, but for which it is still very easy to upgrade software. Debian names their releases off of characters from Toy Story, and "sid" is the unstable branch - remember that Sid was the destructive kid next door ("does not play well with others.") That's their way of warning people that you shouldn't mess with Sid unless you know what you're doing. The current stable release of Debian is "woody", and the testing release (soon to become the new stable - and it is pretty stable now!) is "Sarge."
The variant of Debian I run is a commerical release which makes older versions freely available. Libranet (
http://www.libranet.com/) version 3 is supposed to be out soon, and it will have a nominal fee, but 2.8.1 works great and is free and you can easily configure it to add patches from the standard Debian release site, so you can add patches and keep it upgraded. Debian supports live upgrades, so you can upgrade between releases painlessly, only requiring reboots after changing the "kernel" - the core of the Linux OS.