Google is now confirming problems on the China side:
http://is.gd/99vWkn(link is to a Washington Poststory today)
I note that the Google says it's a problem with TGFW messing with web access to Gmail.
I've never had a problem with Gmail (3 addresses), but I always use an email application for all my email. Outlook Express and Outlook when I was stupid enough to run Windows, and Apple Mail now.
I could never figure out why anyone would access their email through the internet rather than on their computer where you can read it offline and save all the messages, etc. Yahoo (U.S.) charges for that, but Yahoo Australia does not (last time I checked). And even poor Hotmail can be set up for access through Outlook.
If you're still having trouble with Gmail, try setting it up to send and receive through your computer email program. If you don't know how, spend the 15 minutes to RTFM.