Hi Bob,
Welcome to the Q&A Board.
One of the other new features in Elements 3.0 is to bring details out of shadows. I hear it is very good. It also has a built-in red-eye fix and you can adjust white balance with filters if you didn't do so with your camera.
I think you main consideration when deciding is to determine how much image editing you do. For the difference in money, Elements 2 may be all you ever need. Picasa2 offers nice editing tools too, plus it is absolutey free. Elements3 adds some filter effects but for filter effects, I personally like PhotoFiltre and that, too is free. Here's some information about it.
http://www.digicamhelp.com/photofiltre/Yes, elements2 has layers but I honestly don't recall if it has a histogram.