There's nothing wrong with taking a day off every once in a while. My weekends usually end up being my cheat days. You just have to be careful to balance out the extra calories with more exercise/water. The less you deprive yourself, the easier it will be to stick with your diet.
I've read that you can have one "off" day a week, as long as you don't go crazy. Especially since you still exercise on that day, I think that you'll be fine. It really depends on your expectations that week for weight loss. You're basically cutting into the deficit you've been saving up all week; say, for example, one ate at a 200c def. for 6 days out of the week, then you're at -1200 cals. One eats 1700c instead of one's regular goal of 1300 one day, then one is down to -800c.
I think for some of us, having a freebie day is what keeps us sane. I had ramen on my last one (Saturdays are my freebie day). :B
I'm all for the cheat day if helps you feel sane. Just remember that a cheat day is a day to let the raines loose alittle not go hog wild. But I certainly don't see anything wrong with going out to a nice resturant and not counting the calories to what you ate. If you eat well 6 days a week and exersize all the time it's not going to be a big deal anyways to your weight loss. & I believe in order for you to continue to be going on the way your going to keep your self motivated you have to keep sane and if this keeps you sane and makes you happy. A happy you is going to keep you doing and suceeding in the goal of life not jsut weight loss. Take the cheat day, and don't even think twice :)
Over eating by 3500 calories (which is easy to do on a cheat day) undoes a lb of loss. Realizing this I only do a cheat meal once or twice a week where I eat at maintenance. I'm still averaging 2-3 lbs a week.
I can only really speak from experience: I don't really do "cheat" days per say, although I do sometimes not count calories for a meal...for example, I watch what I eat most of the day and stay withing my normal range of calories until dinnertime, then if we're going out or something I might stop counting for the evening and not worry about it.
What I do more often is practice a loose type of calorie shifting--instead of working to only eat a specific number of calories a day, say 1300, I give myself a range to eat within: 1200 - 1600 or so. So some days I eat more, some days I eat less...this allows me to enjoy treats and eating out but still lose weight by having high and low calorie days depending on my activities.