There actually is a top pec to some degree, or rather an arrangement of fibers that will activate a little more on inclined movements.
You're right about the outside pec though.
As far as which incline is best - most of them are at certain times. Just depends what you want to emphasize. Also, rather than popping your ass off the bench (to those who posted that) just put your ego away and lower the weight to one you can handle correctly. You shouldn't be able to use the same weight at 45 degrees that you do at 30. Don't try to, use what's appropriate. Problem solved.
This stuff is easier than some folks make it out to be...