Hi Matt,


I have experience with CS3 and Lightroom 2 and have recently compared CS3 to CS4. With your student discount, I would certainly opt for CS4 asit offers significant new functions and features over CS3 that make it worthwhile depending on your specific needs. CS4 Extended includes significant "premium" design features that you may not need so I would figure out if you really need those premium features. Maybe the plain old CS4 version would do. New features of note are CS4's enhanced camera raw processing capabilities and something new called content aware scaling. Many other existing functions have been enhanced as well. Content aware scaling will allow you to automatically recompose an image as you resize it while preserving important areas as the image adapts to the new dimensions. I do not have experience using any version of Photoshop on a Mac computer, but based on what I read the differences are only cosmetic. The functionality of Photoshop is the same regardless of whether it runs on a Mac or PC. There are also recent CS4 reviews in most of the major photography magazines that are available via their websites so I would check them out for more detailed information.