as said i love google calendar for it's simple but powerful user interface and it's integration with gmail. what i really miss is synchronization with outlook and my palm t3.
vast numbers of users request a simple sync tool from google but they seem to be deaf and leave this basic functionality to 3rd parties. nasty!
if i find time i'll come up with a summary of my findings!

As already stated i'm Google addicted (too much).
- GMail is wonderful as i never loose any eMail (which i frequently did when i used e.g. GMX & a local eMail client).
- GCalendar is so well designed that i simply love it.
- GoogleReader is a pretty fine RSS reader.
- Picassa is the best free photo organizing software i know about (picasa web albums cannot reach flickr i have to admit).
- Blogger is what you're currently reading.
Today i have to praise GCalendar even more! RememberTheMilk and WeatherUnderground integrate tightly into it via iCal feeds which makes it even more usefull!

Play around and enjoy the fun!