I'm trying to collect advice and utilities to make better use of the Google Apps on OS X, in particular Gmail, Google Calendar and Google Docs.
Gmail
I tried Mailplane but I find the ratio price/features a bit too high so I decided not to buy it.
Now I use a Fluid's app for Gmail and I installed Google Notifier to have growl like notifications.
Google Calendar
Idem, Fluid app, and Google notifier.
I'm syncing my google calendars with iCal but it is only one-way.
Edit
As @Rene Larsen said, it is possible to use CalDAV to sync with Google Calendar.
I have my own calendar, I shared calendar that I created and I calendar that I can only view. They appear like that:

Is it normal that each calendar appear in its own list ?
What do you use ? How is it possible to improve that ?