alright, so i've recently purchased the L2 and R2 triggers for the ps3 controller, and wow.
they're pretty amazing and i was skeptical into buying it, but it went on sale for Buy one get one half off, so me and my buddy got one too.

so to get back to the point, i was wondering what other kind of accessories i should get to improve my gaming?

grips for the controller? FPS freak (saw these on amazon and reviews seemed good)? etc.

i already have the headset, and i find no use for keypad.

to add more, i mainly play FPS games, such as COD.

TURTLE BEACH HEADSETS!
I'd recommend the PX1. (look here http://www.turtlebeach.com/products/efpx1/home.aspx)
Possibly a grip for the controller.

That's about all you need. Some people find it necessary to use modded controllers so they have rapid fire on their semi-automatic weapons but I'll leave that to you.