The Wife and I are suddenly both able to jog something like 2.5 miles continuously. This is a big jump from where we were. I definitely believe a course change is the prime contributor to the improvement.
Since September of 2007, I've manage to whittle myself from around 220lbs to 190-ish. I only have this to say: It's a lot of friggin' work.
I cannot tell you how excited I am about GTA IV. The multiplayer action looks like a flat out hoot. Email me if you want my Xbox Live gamer tag. ;)