Could you post more information so some better replies could be given?
What games you want to play will effect this, as you mentioned wanting optimal settings in every game. A universal setting for all your games is in fact possible, but you won't get the best for each game as you want that way. Based upon the resolution you run, I can get an idea of the level, but computer specs are still needed.
on the limited info I have I guess I can see you can get the game running playable at 1280*1024. Optimal for that (without any knowledge of your computer hardware) would probably be every graphics option set to nearly full, with maybe some AA.