I've been using a G9 for exactly that for the last year and a bit. Works really well so long as there's sufficient light. With low light the results can be a bit hit and miss, which is why there's not many pictures in the trees in my flickr.
I really like it. Problems I've had are debris on the sensor. Sent my first one back. Second is better but has some dirt on the very side that's visible on some focal lengths, it's easily cropped so I haven't sent it back. Other issues, lens slightly scratched, probably due to me trying to clean it and remove the debris on the sensor! The ISO knob doesn't select 800 anymore too. It's been in a camelback five or six days a week over the last year though so not to shabby.
If you want to see results then there's loads here: my flickr[/url]
When I need to replace my camera I think I'll get another one the same. I can't justify the bulk of a SLR although it'd be nice for some occasions. My G9 is always in my pack so I have it when I fancy a picture. I use it with a JOBY gorillapod thing.