Here's a chart with some statistics on steel tubing materials. The lighter the tubeset, the more expensive (usually). Disregard the weight limits, as they are very conservative. However, if you are very heavy, some of the super-featherweight tubesets might not be the best idea.

This is a great website with some scans of catalogs of some now obsolete component makers, including Suntour. It will give you some idea of the component hierarchies, but it is by no means all-inclusive.