One of major weaknesses of Google Wave is that you need to specifically check the site to see if any of your waves have been updated. Google Chrome extensions are available, but don’t yet work on the Mac (besides, as we’ve already established, Google Chrome is slower than Safari on the Mac).
A better solution may be the Unofficial Google Wave Notifier for the Mac. It’s a free download and, in my 2 minutes of use, seems to work pretty well. It basically sticks a little Wave icon in your menu bar and displays the number of unread messages. If you click on the menu, there’s a link to go to Google Wave, as well as a list of the Waves with unread messages.
I still find Wave a bit clunky for most uses, but this is a step in the right direction.