I think you are far better off saving your actions and copying the actions themselves over to the Presets folder and also backing them up to another location on your hard drive (or on another media). Otherwise you run the risk of losing them all if you reinstall or even crash or reset preferences.
I agree that you should save all your actions to another location, and after you install CS, copy them into the Presets/Photoshop Actions folder. It makes good sense to back up your actions this way, and it simplifies adding them to CS.
You should also save the contents of your Plug-Ins folder to another location if you have third party plug-ins. There is known problem in which CS will come up with an error message each time you run it – "can’t find PDFL50.DLL" – although the program will load properly after you click on OK. I gather that most people don’t come across this problem, or maybe they don’t have the third party plug-ins that cause the problem.
The solution is to uninstall CS, and then uninstall PS 7 and delete all the plug-ins from the PS folder. Then reinstall CS, and restore your plug-ins. When you reinstall CS you will need your PS & disk handy for upgrade verification.
I don’t suppose for a moment that CS is the most important upgrade in the history of Photoshop, but for me CS has brought Photshop to the level that makes it easy for me to do all the things I’ve ever wanted to do in Photoshop, and more than I expected was possible. ,
