I agree with pg. If your site is targeted to mainstream, as opposed to geeks or early adopters, you would have to fight really  hard to go against default mind-share people will have for dot com. Remember, many people still don't know "what is a browser?" <a href="http://www.youtube.com/watch?v=o4MwTvtyrUQ" rel="nofollow">http://www.youtube.com/watch?v=o4MwTvtyrUQ</a>