In case you missed it, check your Software Update, there is a important Safari upgrade in there.
I classify this as "important" not because of the security fixes included, but because Mail.app is now working properly again.
With the last Safari 3.1, I stopped being able to paste plain text inside a mail message. I would copy something from TextMate or a Terminal window, and when I pasted it into a Mail.app message window, the line breaks would be lost.
This is most likely related to the same bug that Gruber complained about.
Anyway, Safari 3.1.1 fixes it, so I would strongly recommend that you upgrade to it.