For those who have just got their new Gmail accounts here are some nifty tools :
(PS remember that after a while you'll get invitations to send out, post in the other Gmail thread when you do)
The Gmail notifier. Windows systemtray program, tells you when you get new gmail:
http://toolbar.google.com/gmail-helper/
POP your Gmail, instructions here on how to download the web mail :
http://www.gnotify.com/gpopper/
Here is a Gmail applications link collection:
http://www.marklyon.org/gmail/gmailapps.htm
...and if you want to get really advanced why not mount Gmail on your linux filesystem
http://richard.jones.name/google-hacks/gmail-filesystem/gmail-filesystem.html