I've been a fan since the seventies. There is tons of information and bios of the band in books and on the web.
Essentially, Pink Floyd was led by singer/guitarist/songwriter Syd Barrett in the late 60's. He started them on this weird light show and cosmic sound track. But by 1968 he ha so completely fried his brain cells on acid that he became virtually catonic, especially on stage when he would often just stand there and stare into space. David Gilmour was brought in to replace him mainly as singer and guitarist, while bassist Roger Waters took over most songwriting duties. The rest is history.
I consider their finest period to be just before they got really big. The first two albums, Piper at the gates of dawn and Saucerful of secrets are childish in parts (Barrett's influence), and sometimes brilliant (hints of things to come). They didn't really know what they were doing on those albums. Ummagumma was the 3rd album, and was half live and half studio. You really have to be stoned to enjoy the studio side, but the live cuts are fantastic, especially after you've been polluting your own brain, if you know what I mean. Then came Atom Heart Mother and Meddle, both of which are truly excellent. Then came Dark Side, Wish, Animals, The Wall, and then the band exploded out of existence with the Final Cut, where you could almost hear the burning hate the members had towards each other. They never played together again.
The pity of course is that, unlike the Who, Rolling Stones, and many other bands who do reunion tours, they are all still alive, and they won't look too silly playing their old music in their 50's and 60's. But I don't think they will ever make up their differences with Roger Waters.
The only thing you should feel when shooting a terrorist: Recoil.