I agree with most of the Americans that have replied saying that they enjoy the sound a British accent (or at least what we think is British) but find our own accents easier to understand. We always enjoy the more exotic. I personally prefer the "small town america" accent that a lot of people associate with cowboys.

I also fully agree with the statement that as long as you use proper grammar and are clear, I could care less. I called a company to order something I *needed* and was so disgusted with the operator's improper grammar, rude manner, and totally incoherent english (yes, he was from the US, I went to school with kids that spoke the way he did) that I was inches away from canceling my order.

I have heard that when you're traveling, and you have an American accent, it's better to say that you're from Canada. I'm not sure how true this is because I've never done much traveling. But Canada's neutrality might be admired by some and disliked by others.