I read bits about the F40, seems to be a worse option than the 31....
The reason why the the Fuji is tempting over here in the UK is that I can pick it up for about £130, whereas the SD800 is £200 and the SD900 another £20 on top of that -- this fact alone might surely suggest the Fuji is the one to go for.
After some serious decison making tonight, I've decided the A640/710 are too big, which does leave me wanting an ultra compact instead....
I looked at Casio, Panasonic, but they don't seem to be as good in the reviews as Fuji and the Canons.
But my concern with the Fuji is simply that when I go abroad to hot countries, with bright light, I am going to start running into problems.... Although I have seen outdoor shots with it and it looks ok to me..
So everything seems to point to the Fuji, but then when you consider build quality, you start to consider the Canon once more..