The newer point and shoot are all pretty great and very similar to each other.
To be extremely nit picky, I would rule out Nikon because it's minimum aperture is 3.3, significantly narrower than Canon's 2.7 and Sony's 2.6. If you're unfamiliar with aperture, the smaller the number, the bigger the hole on the lens
is. That means the smaller the number, the better the camera performs under low light, and the depth of field (far away objects look blurry) is better.
Between Canon and Sony, one thing I noticed is Canon doesn't take as many memory devices as Sony. I don't know what all the technical terms mean, but Canon only takes SD while Sony takes a bunch. Again, I don't know if it even
matters. Just something you might want to look into it. Also, Canon doesn't have as many file types as Sony, but it's also something that I suspect doesn't really matter.
Hope that helps and doesn't come too late. But I think all of them are sweet.
Personally I only buy Point and Shoot that shoots in RAW. But I like the total control over RAW photos, and I post process most of my photos, so it may not be a consideration for you. What's interesting is iPhone 4s' camera is so
great now, I don't even use my expensive P&S that shoots RAW! I just rock with iPhone and a DSLR.