I've mentioned how you can add a few extra flourishes to your Google account thanks to Google Labs, but if you're also a full fat Google Apps user there is even more up for grabs.
I don't just mean a user of the Google Apps on a standard Google account. I'm talking about Google Apps for your domain, where you set-up Google as the service provider of email and other services on your own domain.
Google Apps is free for smaller users, but there is a wealth of power available on top of everything you already know Google for. Many other services can be plugged into your domain through the Google Apps Marketplace.
It's mostly about being better at work -- productivity apps, finance apps, customer and project management, and many more. Some are free, some cost serious money. All of them show why it's a good idea to explore Google as the back-end to your own domain name.