Like just about anybody else on the planet, I spent some time tinkering with LiveSearch this Sunday, and have finally had time to test it under IE 6 at the office and enable it for all user agents. It works, but keyboard handling is shot to bits in Safari and IE due to the way the generated XML is referenced (I was never keen on the idiotic firstChild.firstChild.nextSibling notation, and with dynamic code generation and DOM variations thrown in, it becomes a right pain to debug, even with Firefox's DOM viewer).
So I disabled keyboard navigation on the search list until I have the time to fiddle around with it a bit more. It is, however, high on my list of things to improve, because it's so damn intuitive to start typing and try to jump down into the list as soon as it appears.
And yes, I am aware that the lists' color scheme sucks. I was setting up stuff on my Fedora laptop and lacked decent graphics tools to pick out a matching set of colors.