I have played so many FPS I have lost count. Anyway, I used to never select "invert mouse" with these, I just used to leave it as is. Just recently, I have gotten into third person shooters, like BloodRayne and GTA3. When I started playing these, I found I was more comfortable with "Invert Mouse" selected - I guess it had something to do with seeing the character in front of me, and seeing where they are aiming. Now, when I go back to FPS, I feel all awkward! I don't know whether I should invert my mouse or not, and which way points up and down anymore! (My Q3A skills are slipping because of this - blasphemy!!!) So, do you invert the mouse when you play games?