Well I pulled the trigger (or is that clicked the shutter) on the S3 purchase. Found a store model in an officemax for $223.00.
Now I can say firsthand that the S3 is substantially better in low-light than the S1. The S3 sends out a neat green pattern that helps it focus in low light. Plus, the autofocus is roughly 4 times faster than the S1 in similar lighting situations.
Even without CHDK, I'm already pleased with the purchase.
Now I have to buy a new card reader because my old SD compatible one won't work with my new SDHC card. It's ALWAYS SOMETHING, ain't it?