The magazine I write for prefers a minimum of 6 megapixels. I have a 6 mp Fuji FinePix S7000. Not a pocket camera but it gets me to the required 6 mps.
It takes pretty sharp images.
I would look very hard, though, at Canon. Their digitals always seem to be top quality. A friend of mine takes incredible ditital pics and that is all he uses, from the small pocket size to the SLRs.
Personally, I have had great luck with a 4MP Nikon CoolPix 4300, which is light enough to carry in a small pouch and takes great pics. I think you can get a 5MP Nikon now at a fairly reasonable price.
. . . deliverance will not come from the rushing, noisy centres of civilization. It will come from the lonely places. - Fridtjof Nansen