Photoshop Elements 2.0 for most things, although I would like to upgrade.
Picasa for general organization, browsing, and "reducing" file size to e-mail smaller versions, etc. I also like the scrolling feature better than the Browser in Elements 2.0
I've downloaded GIMP for XP - a seemingly very powerful program - I've read that it can do almost everything that a full version of PS will do. Google GIMP and you will find not only several executable versions (it's open source code and there are several versions, some of which try to emulate PS in look and feel). You will also find via Google several on-line GIMP tutorials that walk you through the various features. If you are looking for something that is potentially more robust than Elements or Picasa, and have the time to learn it by messing around, give it a try!