Im not sure if its a patch thing, but all my old games (previous to 1.17f) ended in all out war, but now I seem to manage peace so much better, by simply giving the AI a small and meaningless gift occationally .. It seems to work for me on all levels ..
Good idea about the Great Library, id not thought of that, I tended to pick science as and when I needed it ..
However, word of warning .. your assuming your in contact with lots of civs (I always seem to start in the middle of everybody, so it will usually work) .. but if you find yourself miles away .. this would be useless, as I believe the Great Library only gives you sciences from civs you've contacted ..
I like the idea of using gold per turn to subsidise your science expense, so you can maintain a low tax base .. very good idea indeed ..
Just beware of the Zulu's .. those back stabbing rats ..

ha ha ha ..