I've been an avid cyclist since I was in my late teens, and I build my first serious road bike in my early 20's. Some time in the 90's, I tried mountain biking, and found that I enjoy it quite a bit. For me, it's a good way to cross-train that improves bike handling, gets different muscle groups into the action, and basically breaks the monotony that constant road riding can sometimes bring.
Below you'll find a list of my current bikes (not counting Jessica's), and how I've built them up. You'll also find some links that I think are helpful.