Check the off-topic forum, many members here listed Still Life as their favorite Opeth cd.
Whenever I am on this site, it seems like the most criticized Opeth cd is My Arms, Your Hearse, which is my favorite Opeth cd, and by far.
Personally, Still Life is my least favorite Opeth cd. Why? Because to me, it just doesn't have the "hooks" that the other cds have. I enjoy the first two songs, but after that, the songs seem boring or not as memorable to me as compared to their other cds, and I don't find myself wanting to go back and listen to it as much as I listen to their other cds, especially MAYH.