If I'm doing the elliptical, if I remember, I wipe down the handles before I use it. I usually don't think about it, so I wipe them down when I'm down and sanatize my hands right away. I also try to be conscious to not touch my face. As for free weights, I can't really walk around with those wet cloths when I'm teaching my aerobics class and we're doing weights, so the first thing I do is wash/sanatize my hands. :) Those cloths at the grocery store are a good idea though. Those cart handles can be pretty nasty even when it's not flu season.
Hopefully all of us will stay healthy. Besides the fact that it would suck to be sick, that would really kill my workouts. I usually go to the gym when I'm sick, unless I'm really, really sick, or throwing up with the stomach flu.