Undo / History options in Photoshop CS

Hey, sorry I have to bring up yet another “is the upgrade worth it” thread. But this is really bugging me.

I use PS 7 at home, and have determined that my money is better spent on food than a copy of CS. But my school has CS installed everywhere, and I really, really want the ability to use CTRL+Z to Undo and CTRL + SHIFT + Z to Redo. it seems CS only lets you toggle Undo and Redo with CTRL + Z, which is the default setting in 7, but in 7 you can easily change the setting in General Preferences.

Please someone tell me they didn’t do away with this feature. I can’t think of a single situation where toggling between two states would be favorable.

Thanks for your help and/or confirmation of my fears.
Okay