Microsoft lately released a beta version of its new Live Photo Gallery. This is definitely getting Microsoft closer to competing with Google's Picasa2 product; the final product will have to get a lot better performance-wise, but it definitely shows promise.
It's going to look very familiar to anyone running Windows Vista, from which the UI was borrowed. But it includes some great features -- such as panorama/stitching, better color/saturation and exposure tools (including histogram) -- and more I haven't yet tinkered with.
A lot of people seem to really like the automated connection to Live Spaces as well. I have a Spaces site, but I do my publishing today on Flickr.