Frankly, it's not close: DSOTM and Animals are firmly entrenched in my top 50, with WYWH in my top 150, while the pre-DSOTM period has one top 100 album (Piper), a probable top 150 album (Ummagumma, with a live album that would be rated much higher but also with an inconsistent studio offering) and a couple of others that might make it into my top 200 (I've never actually bothered to rank my collection out that far, this is just a guestimate based on my site's ratings).
There's little question in my mind that the band really figured out how to best focus its talents around 1972, around the time of Live at Pompeii and the DSOTM sessions.
Given the fact that the band has its own wing in the R&R Hall of Fame (run by Rolling Stone), you'd think that would mean that RS loves their catalogue, throwing out stars to them in a way reserved only for the Beatles and the Stones. A look at the shows that DSOTM and WYWH get 5 stars, Piper at the Gates of Dawn and The Wall get 4 a piece, and all the rest 2 or 3.
Given that the guide makes it a point to denounce the remainder of the band's catalogue as experimental garbage, it confuses me how a set of four albums can somehow merit this much praise.
Roger may not have been the main songwriter for most of the band's life, but he was certainly the band's dark, bitter soul, and he brought a number of things to the table.
He was an effective lyricist, a good writer of bittersweet acoustic ballads, a master of atmospherics and an aggressive user of sound effects to help drive home his points and make the overall sound more powerful.
Moving onto the band members themselves, I'd have to say that Pink Floyd had one of the most fascinating internal dynamics of any band that I know.This is a band that makes no freaking sense, and I love them for it.