So it looks like it's a CSS/JS issue. I ran a quick HTTP trace and noticed that /admin/dropdown.js was 404ing. I then re-created a radiant project and sure enough that JS file was missing from the initial set of files radiant generates. dropdown.js is in the Git repo @ https://github.com/radiant/radiant/blob/master/public/javascripts/admin/dropdown.js - it was updated a day ago :)
So what gives? I did a quick sanity check against the live Radiant demo and http://demo.radiantcms.org/admin/pages is styled and behaves very differently from what I'm getting out-of-the-box the radiant 0.9.1 Help!