In reply to The Lemming:
> Care to share the best image that you have taken?
Further point: when it comes to landscapes, I think the best pictures are always of special, fleeting moments of light (revealing 'nature as an artist') - but few of these will be more important or 'better' than any other. There may be dozens of them in one location over quite a short period of time (e.g a few days). They will each be special in their own way. The sort of pictures I like, such as those by Nicholas Livesey, of Snowdonia, amount to a kind of portrait through time of an area - a portfolio of sorts. (Which is what I tried to accomplish in my mountain landscape books.) But to get back to the original question, I suppose the 'best photos' will always be of important events involving people, or portraits. In the climbing world, the pictures I've been proudest of are of some of the pioneers (e.g. Brown, Birtwistle, Harding, Dawes, Syrett, Elliott).
Final point: I think one has to be very careful not to get over-precious about one's photographs. The subject plays a huge part in an interesting picture, as well as the person who presses the shutter release. Of course, if the shot has involved huge technical difficulties (such as in the old days when we used medium and large format cameras with slow film stocks, and when each frame cost a lot of money, as well as quite a lot of time and effort to set up) there was more to be admired in the medium itself.