Also, there was a name change. In Photoshop 7 they were called panes, but when Adobe bought Macromedia, they were renamed panels. They are the same thing except for the name.
In Edit > Preferences > Interface, you can select a lighter color to look more like PS7
The shortcuts for Channels were changed in CS4. Ctrl+1 is now 100% zoom instead of the red channel. The shortcuts for Undo were changed a couple of versions ago. Ctrl+Z is now multiple undos. Both can be set back to the way they used to be (legacy) in Edit > Keyboard Shortcuts.