Welcome aboard the board!
I think it's a common theme to 'grow' out of collecting for a few years. for me it was primarily because I wasn't into beast wars, and had no idea that the few following series even existed. I was drawn back in when Alternators/binaltech started coming out around 2005 or so.
I'm a big fan of the movie toys, the realistic alt modes and complex design really keeps me interested.
good luck in your search.