Guess ya didnt read the main text of the post
I always shoot at the lowest ISO possible until it becomes unreasonable. I like to take advantage of whatever daylight I get and get nice, noise-free images until it's no longer an option. That's when I bump the ISO on up, and get the noisy crops. If I had a longer focal length lens than 200mm for sports it wouldnt be such an issue at higher ISOs as I wouldnt have to crop nearly as much. I also wish I had gone with at least the 40D as it apparently handles higher ISOs better than the Rebels. I'd love for some relatively noise-free ISO800+ shots at night, it's just not feasible with the Rebels.
I did and didn't, I normally shoot ISO 100-200 but when in twilight or nearing darkness I always bump up the ISO. With my D200 I would try not to go over ISO 1000. With my D300 I have no problem going up to ISO 2500-3200, after that it looks like garbage. Best way to know how high you can go is get an 8x10 or however large a print you would want and see what the highest ISO you are comfortable with I mostly sell 8x10s and lower and 3200 works pretty well as long as its exposed properly.