Okay, this past weekend, I got some advice that, as unbelievable as it may sound, I had never heard: "you should never play a FPS over a wireless connection". That night, I hardwired into my router, and there was a definite change. Today, I called Comcast because it has been over three years since our last modem was issued, a surboard5101, and they told me to bring it in because our plan was not being fully utlized with that modem. They swapped us out for a DOCSIS3.0 modem, and my goodness, it is like I became a COD God.
I still have to get a new router, and Im sure my performance will drop off once I plug back into my router- but for those of you experiencing terrible lag, check to see if your modem is outdated. I did, and I couldnt be happier.