I picked up the A75 a couple months ago for $150 from Circuit City on a price mistake. Love it so far, but I haven't taken many different types of pictures. Was up to about 4200 pics on my last camera.
Going from a G2 to any $300 camera today will not be a dowgrade. G2 is 3 or 4 models old. Technology is better and cheaper now. I'd say the A80 has just as much manual control and takes just as good pictures as the G2. And, it has a great video mode too.
Like Jato said, pick your budget, and that narrows down the selection.