Before updating to 2.2, I was receiving Gmail notifications just fine. After the update to 2.2... no more Gmail notifications. Somewhat of an annoyance since I had come to rely on it to let me know about Gmail in a timely manner. No sense having it (GMail) installed if it's not going to work properly.
I tested this directly by sending an email to my gmail account from another non-gmail email service. I can log on to Gmail.com and see everything just fine. It's the Droid Gmail notification that has failed.