Here's two minor things about 1.5 that I think are way cool.
When you open a link in a new tab, the link isn't marked as followed until the connection actually goes through. This also works on other tabs, if they contain the same links. It can be a bit disconcerting at first.
The error pages actually work. And they are pretty. When that hit the nightlies, I was typing pages incorrectly on purpose just to see the beautiful error page (for instance, try
http://www.osidufa.com/).