i have often pondered that question of what i prefer..opening from 1-3 or 4&5, and i have to say first off the opening for seasons 1-3 fits those seasons,it fits the boys where they were,what was going on in their lives, season 4 was named the coming of age episode, so i liked that they changed the opening to show that, that the boys have grown up,their careers have all changed. so if i had to choose just 1 opening, i would say 4&5..
p.s season 4 cd, is my favorite "go to music" for just about anything..