Growl is a great notifier for Mac OS X and it has some features that can make it even better. If you go in the Growl settings in Apple System Preferences, you can modify the "Network" settings. From there, you can enable "Listen for incoming notifications". This will make your Mac available in "Forward notifications to other computers" on other Macs. It is a great way of having notifications from both a laptop and a desktop show up on both Macs.