First Set: Nuparu Inika
First Average Set: See above
First Titan: The Nui Rama, I think those count. If not then the three Titans of 2004, I bought all of those at the same time
First Small Set: The Turaga (yes, all of them)
First Favorite: Nuparu Inika
First Disappointment: Stars Takunuva (I never bought any Av-Matoran)
First Vehicle Set: Takunuva and Ussanui.