Best photoshop ?

I know there's already a thread about Photoshop but it's packed with trolls and not exactly what I want.

I'd like to know what - in your opinion - is the best Photoshop version. I learnt on 5, then used 7. When CS was released, I heard that it was a memory hog and didn't go any further. Is CS2 is any good ? Support for HDR looks nice but is it worth the additional memory consumption ?

I don't want any alternative: I don't like PSP at all and I'm not getting used to GIMP even if I usually go with Free Software (I should try GIMPShop, though).

I use CS2 on the pc just fine. The Mac version is more fine tuned (you can, for example, adjust key variables on the palette in the mac version that you need to right click and select the menu to adjust on windows) but since both are WIMP GUIs, this decision to finer tune the Mac version is just that; a conscious decision by Adobe. They could do a perfect port of CS2 Mac version to PC with no noticable changes, they just don't.