This is a no-contest. Supertramp is dead. All hail Pink Floyd.
What does one say here that isn't incredibly obvious? Supertramp were okay, nothing special in my book, but Pink Floyd were downright amazing.
What angers me though is there are all these kids today listening to Pink Floyd and claiming to be big fans, yet have never even heard of Syd Barrett! It's ridiculious. While post-Barrett Pink Floyd remains the most popular and acclaimed work they ever put out, I for one always preferred Pink Floyd when Barrett was leading the band. He was simply a musical genius, mixing British pop, psychedelic rock, folk ballads and even children's nursery rhymes into this insane mixture that was immediately recognizable and among the top psychedelic rock ever produced.
So do yourself a favor people if all you've heard is "Dark Side of the Moon" or "The Wall", and buy or download their first album, "Piper At the Gates of Dawn". It's total mind-pleasuring genius.