Hey Black, is that the new 5 1/2 floppy drive, or is it one of the older 10in drives? The counter on my tape drive is busted and I'm looking to upgrade...
Personally I'm just using a standard Microsoft keyboard with an optical wireless mouse. The only issues I have with the mouse is that it is sensitive to the type of mouse pad I'm using. If the pad isn't completely flat (sometimes it can get an air bubble under it) the mouse will react slower. I haven't quite got that one figured out, but the optical is much better than having to clean the roller all the time with an analog mouse.
As far as the graphics card, i did upgrage to a Geforce 9800GT for Black Ops and Medal of Honor, but not that big of a change for COD4.
The bigest impact to my game is my mood and my gun choice. Sometimes I push to rush in and shoot any & everything when I really should be doing more sniping. Other time's I just get bored with sniping and stop paying attention. So my advice would be to play around with the different classes an make them to fit your style AND the maps/game types that are in the rotation.
Everytime we change rotations, I have to make new classes or at least play the ones I have totally different. But like most of you know, that's the fun part.
Good luck. And BTW, if you ever see me say "Catch", run!