Upgrade to a nine-speed drivetrain

I picked up a Tiagra FD, cassette, chain, and 105 shifters on eBay for all less than $200 and got some cables and cable cutters at the LBS and spent an afternoon putting everything together. It was a lot of fun, but took a lot longer than I though, especially since I did spend some time cleaning everything. Here’s my BikeForums thread detailing the upgrade, and a Flickr set of the photos.

My aim is to slowly collect compatible parts from eBay or Craigslist. Anything relatively new in the Shimano 105 or even Tiagra range is good enough (better than Sora) if the price is right. Full 105 would be best, but there is a considerable price jump. Just getting my bike nine speed in the back would be good enough from there and then I can think about upgrading further or even getting a nicer frame and building it.