Hi Barry
I am also a Gmail fan and use Gmail to run my Neil<AT>redcherrymarketing.co.uk email.
The other benefit is when collaborating with companies and individuals we can easily share documents and update them using the Google documents interface. This is a lot easier than firing documents back and forward as attachments. The other benefit is you are always looking at the same document.
There are lots more useful benefits of using the various Google apps as a small business. Too many to go into here.
Big thumbs up from me.