1. PS CS2 and CS3 (my main app is CS3)
2. Adobe Lightroom (recently upgraded to v.2.0 from 1.4)
3. Elements 5 and 6
4. Picasa
5. Nikon Capture NX 1.01 and 2.0
6. Nikon View NX to cull the RAW files initially
7. MSPaint (yeah, I tried it... lol)
8. Bible Pro
9.DxO Optics Pro
There are a few others that I played with. I decided on CS3 and a lot of people are working with LR 2.0 for speed reasons. My LR skills are freaking weak and I am a lot faster in CS3 to date.
I'm sure CS4 will fall in there at a later time, I;m just not even at the stage where I can exploit a lot of what CS3 has to it's fullest... yet.
Edit: I forgot to add DX0 and Bibble Pro and DxO Optics Pro... lol