I personally hate parallels. I had xp installed through vmware fusion so I could run Autocad and it was so slow, even after I tweaked all the settings, that I just went back to bootcamp. If you think about it, it takes just as long to load up the virtual disk in parallels as it does to reboot in bootcamp. The difference is, in bootcamp your computer isn’t having to share processor and memory to run both OS’s. The downside is you have to save all your files to an external hard drive to transfer them back and forth. Also, as far as CS4 is concerned, its pointless to run it on any OS that isn’t 64 bit. The only real advantage to CS4 over CS3 is that it allows you to use more memory for programs like photoshop.