I'm thinking that the Canon s90 will be my next point and shoot: it's the right size, the image quality is outstanding for what it is, the high ISO noise is reasonable, and it shoots RAW with full manual control. It is frightfully expensive.
My usual walk-around camera is a a Canon g9 that I either carry in a jacket pocket or wear around my neck. It's not exactly light, but the controls, image quality (when kept at ISO 200 or below) and tank-like construction are all nice--as is the 210mm equivalent long end of the zoom. 35mm equivalent on the short end is a little long for scenics, however.
This spring I went on a multi-family backpack trip in Big Basin State Park (CA) and carried a Canon XSI with the 18-55 IS zoom, and I'm glad I did. Even in fine weather it's incredibly dark under the redwood canopy, and everything was shot at either ISO 400 or 800. This was the heaviest single item I carried on that trip, and I just hung it around my neck (without a bag) the whole time we were walking.
I think optical viewfinders on small cameras aren't worth much except for prolonging battery life, but carrying an extra lithium battery isn't much trouble at all. I also find that today's cameras are weatherproof enough for my needs, and I use all of them in the snow and rain without any trouble.