http://www.fundinguniverse.com/compa...ycles-history/

Good starting point for the history of GT. 1996 was a pivotal and tragic year for the company and as such many GT fans (like me) tend to have a diminishing appreciation for bikes after 96/97.

BikePedia can help with the 'heirarchy' aspect. I don't know much about their road bike side but am a GT MTB fan. The Titanium Xizang is highly coveted and the 6061 aluminum Zaskar's from the early 90's to '97 are also in demand. These are probably their two most iconic MTB frames (both hard tails w/triple triangle).

I have 3 Zaskar's and a steel '89 Karakorum K2. The K2 I have had since I bought it. The Zaskars I have purchased more recently. You can get a decent Zaskar frame for around $140 and I've bought full bikes for $200. Be warned - there are people COUNTERFEITING Zaskars. They take a lower end GT frame and throw some Zaskar stickers on it. Look for a flat GT end cap on the top tube (NOT curved) and a 6061 stamp on the dropout.