bbaws,
A poll is not a functional solution to your problem.
You are wrong; absolutely.
Attackers get no postive or negative adjustment from ATTACKING from a certain type of terrain or a fortress.
This has been repeatedly tested again and again and your posts and experience are just illusion or misconception on your part.
Terrain effects the movement ability of attackers, but beyond those factors, there is no bonus.
If you are looking at barbarian combat results you need to understand what difficulty level you are playing on because all units will get an attack bonus against barbarians depending on the difficulty level you are playing. This will skew your perception of the results but it has absolutely nothing to do with terrain, city, or fortification status of the attacker.
You can find these attack bonuses as they apply against barbarians by looking in the editir at the "Difficulty Levels" tab. As an example, the default attack bonus versus barbarians on Warlord level is 400%. You have to play at Deity level in order for there to be no attack bonus versus barbarians.