Katatonia is generally a pretty song-based band I think, but Porcupine Tree for instance is more an 'album' band, especially their more recent albums.
I agree with you definitely. If I ever get up the urge to listen to PT, I have to soak up a lot of their music. Something about their sound just isn't doing it for me any more. I'll have to revisit some of their stuff again.
I actually prefer Blackfield to PT any more. Is that weird?