AdWords has done a lot for my site so I don't want to remove my ads, but I'm wondering if there's a way to dissuade people from repeat clicks.
Just look for a script that is cross browser compatible. It's been a while since I've done it so I don't know how Firefox figures into the coding.
Search on "bookmark site script" or similar
Israel
Bookmark suggestion is a good diea, I'm just suggesting the reality is, in this situation, that you won't be able to stop the behavior you're concerned with, and it isn't really a bad thing (in light of conversion probability behind it).