The 16-80 is a f/3.5-4.5, not a 4.5-5.5
There is also a 24-105 f/3.5-4.5. and a 16-105 f/3.5-5.6. But, I think you're probably better off with the zeiss 16-80 or the new 16-50.
Awesome that you're getting an A77, I will most likely be getting one as well, but I think I may delay gratification until 2012.
Not all Sony/Minolta high grade options are labeled "g".