My favorite was the aforementioned Sam Adams Light (guess you didn't like that?)
I have had to swear off of that... low-carb diet since November. I have lost 70 lbs., but beer has pretty much become a thing of the past.
Best low-carb beer I have found is Budweiser Select. After that would be Michelob Ultra. But unless it is a health necessity - stick with the Guinness! "D