Not that it bothers me too much, but I always thought U&L was still in beta because of the favicon. It has the same design as all beta SE sites.
Was this a coincidence? Or on purpose?
It's the same concept, although it does look different -- the beta icons are "sketchy", like:
Ours is the same layout, without the sketchy theme; Wordpress is another site with a letter-based icon:
I never really cared for it, but I think Jin just had trouble coming up with a graphic that would represent the site well and look good in a small format. If anyone has any ideas I suspect we can get a new one made (trying to find out)
I kind of like the license plate, if we can have the rights. It's not square, which may be a problem.
The penguin is by far the most popular (and recognizable) representation of Linux. Although it doesn't quite capture the UNIX idea, linux is the currently most widely-used unix (needs citation :P).
Maybe a penguin on top of the (color-shifted) stack-exchange bubble?
+ = ?
I'm no designer, but I thing the logo would gain if it had an X in it. U-L-X looks more "unixy" than U-L.