The problem is not "Who do I want to see?" but neither is it "Who do I care not to see?". The additional problem is all the acts /artists that I simply don't know if I want to see or not. The default position, which is listening to all of them, is simply not an option.
It is true that I have seen both Sigur Rós and Belle and Sebastian live before but that is not to say that I don't want to see them again.