What I do personally is have a goal of how many calories I eat in a day (1600). It takes a 3500 calorie deficit to lose one pound, so I looked at a few different calorie counting websites and did a rough average of how many I burned in a day. 1600 is, of course, below that...any exercise I do is a bonus in my mind toward that goal of 3500.

I tend to consider exercise bonus, too. If you're eating your exercise calories you're negating the positive weight loss effects. You might as well not do the exercise in the first place (other than the additional health effects, of course).

But the health benefits are nothing to brush aside though... Honestly it should be part of your motivation to exercise, but that's just my opinion.