I keep toying with this, too.
I wouldn't have a problem with giving up dairy, as long as I could find a sub for the good cheese I eat for snacks. I don't drink milk.
I *would* find it difficult to not have whole wheat grains some of the time. I have pretty much cut out most white flour stuff and I hardly eat dessert. But, I do eat Luna Bars for snacks on work days, because they are easy for me to eat in the car! I love good whole wheat bread or bagels. Don't eat tons of it, but...
Don't think I could give up wine.
About 8 years ago DH wanted to lose some weight before we went on vacation to AZ. I supported him by doing a low carb/low glycemic eating plan for 3 months. We weren't super strict, but we did pretty well, after the initial 2 week period that was very hard. I lost 5 lbs and DH lost 10. I don't work out at the same level as some of you, in that I am not "training" for events, but I do do something 6 days a week. Is it worth it? My weight is fairly stable, but I'd love to get it down another 2-3 lbs., so I have more wiggle room.