SD850IS vs SD900 which one is best P&S

am looking for a nice point and shoot, have narrowed it down to the 850IS or 900, both are comparably priced, is image stabilization helpful? does it work well? any thoughts as to which would be best for a vacation/daily carry camera, got rid of my old P&S because it took like 3 seconds to start up and I missed alot of shots
TIA

I would take image stabilization over 2 extra megapixels any day. While the Elphs don't really have a strong enough zoom to make IS an absolute must, it does help with low light shooting. Have you ever considered the SD800IS? That will give you a wide angle lens as well, which can be quite useful.

I prefer IS as well. I am looking to buy a p&s also, either sd800IS for wide angle or wait until Canon come out with a new model with 10 MP and IS.

I'd, seriously, not hang around waiting for a 10 MP P&S. Noise in the small sensors is already pretty fierce; they'd need a couple of major breakthroughs or a significantly larger sensor to get a 10 MP sensor worth using. And 6 MP's enough for an 8x10, easily.

Sd900 is already a 10MP p&s. Does it have less IQ compared to SD800/850? Perhaps it has better optical that makes up for nosier sensor? I didn't want to buy this model only because it's lack of IS also less zoom. I don't know why canon didn't offer IS in this model, there must be a reason.

Optics can't compensate for noisy sensors. If anything, worse optics, by lowering the lens' resolving power beyond the pixel size and providing poorer contrast, might actually help with noise by minimizing differences in the amount of light supplied to adjacent sensor sites.