Canon PowerShot G11 v G10
Both cameras use the same 1/1.7" sized sensor. This means that the G10 has to squeeze in approximately 45% more pixels (or 'photosites' as they're more accurately called) into that space than the G11. Put another way, the G11 has 45% larger photosites than the G10, allowing much more light in and increasing the signal-to-noise ratio.
As the owner of a G10, I can attest to the quality of the images that it produces, but I also understand that I don't need such a high resolution camera to do so. The trade-off of squeezing more pixels into the same sized area is that it increases the likelihood of noise.
Unless you're printing at A2+ sizes, the effect of the reduction in resolution won't be apparent, but the reduction in noise will.
The PowerShot G10 is officially discontinued now, although there are still a few available (it is slightly cheaper). But if you think that the G11 is a down-grade, don't! It will produce better images due to the reduction in noise.
