I bought the Canon G7 in June, and my best friend bought the G9 last week.
This website helped me a lot to make this decision.
Before it i used a Canon A75 and I wanted to have more options and greater abilities, but the step to dslr world appeared too big.
The G7/G9 is a really nice compact, and its somewhat unique on the market.
But with time i encountered that there are some issues like already mentioned here: the ISO noise. The other thing i miss is a wide lense, perhaps 27mm equiv.
I wonder if it will be possible to improve this until the G10 for example.
Unlike other compacts you can use the G7/9 in dimmer conditions, it isnt a bright-weather cam
The application Noise Ninja removes noise but the picture is so blurred that all in all iso 800 and above is quite useless.
The lack of wide lens and and iso noise together make me to buy a dslr.
But a highend compact like this can be always a good extension or a everywhere-carried camera.
There is a thing that aint clear to me: people whine about f2.8
lens but what about an eos 40d kit lense for example: 17-85mm f4
or 18-55 f3.5