OK, this is likely old news, but I pulled up the Southwest site today to book travel and noticed that there is a new design.  As Guy would say, it is quite “lickable” ;-).  Everything that matters is above the fold.  There only 12 links above the fold and they have a very obvious hierarchy.  The 4 main reasons that a user visits the site are the most prominent buttons.  Even the branding image is very well done.  There’s a bit of Web 2.0 flair, but it’s not over the top.