I browsed the default settings to see if i could just turn them off or otherwise limit the notification to my chat box, but I found no such option.
What I'm referring to is the little rectangular window that pops up when you get an achievement.
http://img692.imageshack.us/img692/3441/85971656.jpg
^^pic of my UI^^
I have some bindings, but I also rely on my mouse to click some abilities and the window pops up right on top of my central button stack.
LF add-on that lets me control where the window spawns or change it in any way.