Photoshop users: what version do you prefer?

[ka jowct]

I have PS CS2 installed as well as CS4. I'm most familiar with CS2 and like the interface somewhat better, but am using CS4 as well. I wish I had time to really get some work done with either version.

I have the PS CS5 and CS6 upgrades as well, but probably won't install them until an OS upgrade forces the issue.