I disagree, i don't think music (and many other stuff u mention) is all about taste.
People may be different but they also have many things in common and both these aspects are eQually remarkable.
For example, i think that the best album of 2004 was Colours by Son Kite. I was happy when i found that some people here agreed wih me, that we somehow connect and feel the same in spite of living in different parts of the world. None of my friends listens to this kind of music and the only way for me to share my views is through this forum and these threads (and this goes for many others too). If you find it lame is like a friend told you : "Hey man i found this album really good" and you reply "Fuck off lamer, why the fuck do you bother me, music is all about taste".
I also think that there is such a thing as best. The only problem here is that many albums ,especially from the "golden era" reached the "best" level and it is difficult to pick one. Im sure that mos people here place the mentioned albums at least on the "way above above average" level.
You said that noone will ever agree. But most of the posts here have at least one common album.