Photoshop CS4, not sure when it came out, but, my dad recently got it.

 Spoiler

The interface looks really nice, actually. I prefer this over the old one.

This is the Photoshop common version, I have this one too. Still looking for the Photoshop CS4 Extended version but currently not available...

Yeah... all of the Creative Suite 4 products have this really crisp and smooth layout. I love it.

I think it works a bit faster than before too, no?

It feels the same to me, but other people might say differently.

Yeah, all CS4 applications feature a new tabbed interface for working with concurrently running Adobe CS4 programs where multiple applications can be opened inside multiple tabs contained in a single window, with the same user interface.