Just now something in the styling changed on main that has caused the header row to be aligned weirdly for me:
This does not happen on meta.
That screen shot is from Firefox (3.6, Windows XP). I just checked IE (7) and there my name and the top links don't appear at all! (The SE notification thing does.)
I don't use IE routinely, so I can't comment on the recency of that behavior there.
You may see from the screen shots that my browser window is narrower than the assumed width of our style. To confirm that that's not the problem I made the browser full-screen on a 22" monitor -- same behavior.
Edit: and, a few minutes later, gone. I wonder what that was. (I'm marking this "norepro"; if anyone else sees it, comment here.)
Hypothesis: This just happened to me again, just after receiving a notification that I should review an edit to one of my posts. Now that I think about it, I can't remember the last time I saw the "edit count" bubble in the header. So... maybe the addition of the pending-edits notice pushes the line over in some weird way for me? Yes, that appears to be it -- I just handled all pending edits and the page renders correctly for me again. It appears that the "Mi Yodeya" art is overlaying the center part of the header line after that header line acquires some weird spacing in the presence of the "edits" indicator.