I use Picasa and have just dipped into its creative labs section; I was particularly interested in using the saturation options which are built into Canon and some Sony cameras and I would like to use the Bokeh features which have become quite prevalent on TV pictures, lots at Wimbledon. The saturation is where one colour is retained others are monochromatic (I think) Bokeh is a way of altering the depth of field for effect - how much is in focus how much is blurred. The Picasa options give a limited set of saturation options, nice ones mind, but not how to retain only one colour or at least I haven't found it. As for Bokeh/depth of field none in Picasa but I found one site with brilliant options but was aat $199a bit steep for me I want mine for free.
I usually find my ways around new free programmes but Picasa probably captures too much,e.g. I have got loads of album art clogging up folders and you can't highlight and grab big chunks to send to the hidden section, a real pain.
I do like the ways in which Picasa leaves your original file untouched and saves a copy of what you changed and keeps that in Picasa.
The general features og Picasa are good and i use them often but it is a big miss that they only have limited print sizes.
Never used Windows live but might give it a go if others say it is good. I'll certainly look at the the others mentioned above.