Ah, OK, I thought maybe Moji had some other features. Rikaichan occasionally gets annoying because you may have to switch it on and off if you are trying to copy and paste Japanese text and also highlight and use Rikaichan on text on the same page, but other than that, I love it. (I leave it off most of the time and turn it on when I need it.)

Rikaichan also has a name dictionary you can download, which is very useful, but you need to hit "shift" (twice) to toggle through to its display, which isn't at ALL obvious.