It depends on what you want to do with the scan. If you are happy with just a few basic adjustments, then any editing program will suit your needs. If you want to have the best, then it's Photoshop. Yes it is expensive, but it will do whatever you need it to do.
If you'd like to have Photoshop but don't want to spend the big bucks to get it, find a friend or relative that's in college and have them buy the student version at their college bookstore. The student version costs less than $200 and it's the same as the full version. The only difference between the regular version and the student version is that with the student version, you can't transfer the license to someone else. That means you can't sell it....as if anyone would want to.
Photoshop can be as complex or as simple as you want it to be. You can just use a few features and tools, or you can use it's more in depth features. The thing about PS is that you can always use more of it when you need to.
I don't think anyone knows everything there is to know about PS, so you can learn what it can do at your own pace. I started out with version 3 and I'm up to version 10 (CS3), although I still mostly use version 7.
Anyway, if you want the best, it's PS.....if you are happy with what you are now using, then that is the right program for you.
