Wow you're fast dude! Excellent advice and instructions, hope I can crank something out I like in a few days. I'll probably wait a few weeks to do an animated sig, plus it takes up more file space when you concentrate on making the motion smooth obviously.
As you implied, games are always a good place to get ideas and images from, I might go for a Max Payne sig? So I'd use that faded, noir comic feel with lots of blurring and pastal textures, a bunch of glass, bullet holes, that yellowy bullet time filter, etc. I guess (if I end up shooting for that).