I am an audio engineer turned video editor. I learned Final Cut very quickly and I'm ready to learn AE. I also picked up on Photoshop quickly, but I don't use it that much so I haven't mastered it. Also, I don't own PS.
It seems that it would be beneficial to download the trial version of AE before deciding on what version to buy. If all you are going to use are AE and PSD, Production Premium is what you are after (almost the same price if you buy just the 2 packages only).