hey there.
i went through this some months back ... and ended up buying an s90. however, for me long zoom range was not a consideration. from my experience p&s cameras just aren't up for it. plus i mainly shoot landscapes, travel, gatherings, etc... and use wide lenses much more frequently.
the top contender for me was the LX3. even then, late last year, it was
on its way out an old model. it's also a LOT bigger than the s90. that being said, i think that the image quality from the LX3 is certainly better than the s90. i was shopping for a pocket camera, not only a DSLR substitute, and the LX3 was just too big.
i looked very briefly at the micro 4/3's cameras as well. these though, would be more of a replacement for my DSLR rig than an addition. if i didn't have my DSLR outfit i would go with one of these, but if i am going to carry a micro 4/3 camera i might as well carry my DSLR. one of the guys in my office has the GF-1, and it really takes some killer great photos. the zoom lens isn't all that, but with the pancake it's a nice setup and not TOO big. there are some cheaper ones as well. the E-PL1 for instance, but that thing just feels cheap to me.
a few s90 pictures, just for fun:
my dog at 70mph, dressed as a spider for halloween:
my garage about to collapse, luckily only an effect of the lens:
railroad earth: