For safety reasons I definitely would go with Firefox or Opera. Opera has the advantage of being very fast and, since it comprises something like 1% of the browser market, it's unlikely that anyone would try to develop Opera-specific attacks. The flip side, of course, is that there aren't many people testing it for flaws.
Firefox has lots of addons, which is why I like it. However, I would disable Java in ANY browser, turning it on on an as-needed basis and being careful to be sure to turn it off when done using a website that needs it. Fortunately, the average Joe doesn't use any websites that require Java.