Please forgive me if it has already been asked, but I can't find anything that addresses my specific problem.

I'm building a new skin, and the biggest problem I have with it right now is that the menu is spacing itself out funny. The menu items with submenus (i.e. requiring a little down-arrow) space perfectly, but anything without an arrow has too much space to the right. To make matters much, much weirder, it only happens when viewing the page from the base URL; if you click "sign in" or "register," or even "home," the same page loads with the menu spaced perfectly.

Here's the dev site where I'm testing this:
http://www.sundaypaper.com:8085

I will be very grateful to anyone with a good idea to try. The inconsistency of the problem has me totally stumped.

(P.S. I've only got the CSS working for Firefox and Safari so far, so don't look at the page in Internet Explorer unless you're ready for a CSS-mess-stravaganza!)