So before we start...well I mean now that we've started....except we haven't.
Mac mini - buy from refurbished or clearance at the apple store. For my money, I found the best deal on apple's refurbished store. People somehow believe that their 4 year-old mac mini with a power pc chip is still worth $300, or that last years model is worth $500 because it was upgraded at the time of purchase. In my mind, its only worth premium money if it comes with a year warranty, has an intel core two duo chip and technology from the last two years. Also the newest model has a mini-dvi so only buy one if you know you're getting a mini-dvi to dvi connector (this will come in handy when connecting to a tv).
Kickass Hard Drive, read largest possible mtf'n harddrive available at the time. It has to be a Sata hard drive and it also has to be 2.5" form factor. Typically largest 7200 RPM drives are smaller than their 5400 RPM compatriots. Since we're going for hard drive space, just go for the 5400 one. Get from newegg.com
Some ram - you don't have to max out here. It will do fine with 1-2GB total, but you'll have to make sure you find the right stuff. Not all mac minis use the same ram, so be sure you know what you are doing. Also get from newegg.com
If connecting to an HD tv, buy a DVI-HDMI connector from the apple store or elsewhere. ~$30
If connecting to a standard tv, buy a DVI-video connector. Somehow the mac mini has an above standard DVI connection that allows you to buy this cheap adapter instead of decoding the digital signal and spending $100. Apple doing something that is cheaper than the average computer???Strange indeed! It won't look good, but blame that on your aging TV. You'll also need an s-video cable or single RCA component cable. Adapter is $19 from apple, cable is anywhere from free to dirt cheap.
If connecting to a stereo or if you actually want sound on your tv, you'll need a 1/8" stereo to RCA adapter and a 2-port RCA cable. Cheap at any electronics store, or you can buy overpriced Monster cables (please don't they don't get good reviews anywhere).
Software to download:
Update to the most recent version of OS X by running "Apple Menu>Software Update".
Xcode, Developer Tools - you'll need to sign up as a developer for mac. Free!
Xquartz - just get the latest download
Perian - allows playback of non-quicktime movies with quicktime supported applications.
Firefly media server
MAMP - preconfigured webserver
This part of a compendium. Check out the other parts at:
Step 1: Install Hard drive and ram components
If this becomes a dead link, then it shall be preserved here for awhile