Well after many deliberations I think I have finally decided on my new computer. I'm going to buy a mini-itx case on eBay and a small motherboard to match it. The unit will have a riser card so I can plug in an alternate sound card, tuner card, or network card should the need arise.
This computer will replace my server which I built in 2004 out of spare parts from around Vancouver. Back then I just needed something that I could churn out resumes with while my laptop was in repair. It's still going strong and now manages my entire media collection and all of my communication related archives.
The new unit will sit on the book shelf as opposed to on the floor and should be much quieter than it's predecessor. I will also be purchasing an LCD display so I can retire my laptop.