I'm coming from CS2 so there are so many I wouldn't even know where to begin.

I haven't even mastered how to use CS3 yet. I don't really have a good grasp on using masks for example (or even how to generate one). I seem to be getting better at layers, though. Just recently found the built-in stitch tool, and the built-in HDR tool.

I can't imagine that CS6 would hold anything for me at this time when I am nowhere near using CS3 to its capabilities. Even if it is a really good deal (which it looks like it is). If I didn't have any PS at all I'd probably jump at it.

1poorlady has Elements on her Macbook...I'm pretty sure I am nowhere near using that to its potential either.

The various Photoshop products are seriously powerful. I suspect only professionals use most of the abilities.