Serious Amateur Photography:
If all this preliminary information is correct then there are really two primary differences between these two excellent cameras; the low light / high ISO performance and the articulating LCD screen. I certainly hope the low light / high ISO performance (lower noise) of the new G11 is better than the G10 which is really poor. Especially since this improved performance comes at the expense of image resolution (which I really like for landscape and nature photography).

To be honest, I’m having trouble understanding the benefits of an articulating LCD screen, especially in outdoor conditions. Will this screen be easier to see in bright sunlight if it’s tilted somehow? Does this feature make composition easier? Is this feature aimed at videographers using the G11? Personally I’d have preferred a higher resolution 3″ LCD like that found on the new EOS 50D and 5D Mark II, which is much easier to see outdoors.

gdgt:
I’d recommend the G11 due to the reasons you’ve already mentioned. I’d wait to see how it stacks up against other cameras like Panasonic’s own LX3 since it is pretty comparable to the G10 as it stands (better low light performance, HD video) and will quite likely be a lot cheaper than the G11. Haven’t investigated all the features, but I would bear in mind the price of the G9 didn’t fall that much (if I recall it actually went up) after the G10′s release…

Radiantlite:
Canon G10 is suitable for photographer that shoot in base ISO (100-200) most of the time and care about fine details. Therefore, G10 is great for photographer who works in studio.

Canon G11 has better control of noise, especially shadow in expense of detail and resolution. It also has swivel LCD which is helpful for various shooting situations. Therefore, G11 is more suitable for photographers who work in the field, especially in low light condition.