One day when you grow out of your "everything dark and brooding is totally awesome" phase, you will realize how great Mozart's major-key works are as well. Just because they have a sunnier disposition does not mean they are lesser works (although, admittedly, his minor-key works/movements are very, very, very good). Choosing between the later concertos (which, along with opera, was the category I would say he most consistently wrote masterpieces) is difficult, but 20, 21, 24, and 25 seem to me to be a bit above the rest. Only #26 is somewhat of a let-down.