I love stackoverflow and my love spreads out on other sites that sprung up from the success of stackoverflow.com but one thing needs to be improved : changing sites and getting to know what's been happening on other sites while being on one is absolutely rubbish, especially when you take into account that some people work in high resolution 1600x1200 or higher and are forced to move between beloved sites using 100x100 drop-down menu. Think about something better. UPDATE: just found out that there is some greasemonkey scripts to go around this issue, but that would be embarrassing. Navigation should be build-in on the website.
You can use the footer navigation on any of the SE sites, or you can have different tabs open at once. Also, bookmarks are your friend.