I just got a new Imac and CS4 isn't supported, big surprise. I need a program that can do all the basic photoshop stuff, cropping, shadows and highlights, contrast, unsharp mask, etc. I don't do much photoshop work, I'm old school. If it doesn't look reasonably good out of the camera, I'm not spending much time on it. Is Elements all I need, versus the full, expensive, subscription-based photoshop?
From the sound of your requirements, I'd say Elements is more than you need. I used the full PS years ago, and the new PSE is much more powerful than the old PS.
Or, download the free trial and see if it works for you. You can buy it if you like it.