I've been leaning towards the SD890 IS (IXUS 970) due to the 5x optical zoom. However, the SD870 IS (IXUS 860 IS) looks to be better overall with a wider angle, f2.8 vs. f3.2 in the SD890 IS. The extra 2MB in the newer model doesn't really concern me. Blurry pictures in low light does.
Does anyone else have an opinion? A good chart of all the models
can be found here.