I've become a Google Calendar fanboy.
Now that Spanning Sync has integrated our glorious family domain Google Calendars with OS X's pathetic and lethargic iCal I can view my work and home calendar, Emily's calendar, and the Google Calendars for Minnesota Special Hockey and more.
I can view and edit them on any browser, and on my iPhone. (Albeit with a once daily sync, please ask Apple to open the iPhone Calender API and invite Google in.)
It's fantastic; the work/home calendar integration is almost worth the pain of my Palm to iPhone conversion by itself.
Now I get the bennies, like attaching my calendar to the Firefox Toolbar or embedding my unified Google Calendar Gadget in the sidebar of my Gmail view. Even iGoogle is getting interesting now that I can create a portal with all my embedded Google Gadgets .
 Which would even more useful if Google's directory would clearly separate Google-authored gadgets from the rest of them!
Update 11/7/08: Had to swap out Google Calendar Sync and swap in gSyncit.