You should all really check out the actual security fine print on Gmail.
Google is piloting a new advertising tool, their servers will scan all mail going through their servers for keywords in order to deliver customized advertising to their "free" gmail customers.
They have not given specifics yet on how long they will keep the data in their systems, or how it will be accessed by their "advertizing partners"
Basically they would have data in their systems for some period of time that details the user account, and the subject matter keywords contained in the email transactions, that is scary.
I have spoken to a few people in my company who do corporate email security, and they have warned me to stick with yahoo, or preferably the imap servers that I use from my isp and my work.