Science Fiction Legends

I am currently meandering through the original Star Trek series and thoroughly enjoying every minute of it. The most obvious thing that has struck me is the variety of themes that the series introduced or ventured into. At first glance it seems that almost every aspect of the science fiction genre has been covered to some extent – time travel, mind control, split personalities, computer masters and on and on. It has made me want to start and create some genre categories and start to place books and movies within them. I have no doubt that others have done this over the years but it will be interesting to review my own reading and see where I end up. If you have found a genre in scifi please send me a comment.
I will catalogue my meanderings in my wiki but discussion can happen here.

Now where does one start