I've used a lot of graphics programs. Photoshop is very much a lifestyle of learning, but it is the program I always turn to when I need to get some serious work done. I just don't have the time to program switch to lesser "dumbed-down" apps. I think the pros in the room all have the same question... what specifically are you looking to do?
If you're looking to do basic photo manipulation, like brightness/contrast, pixel dumping, etc... photoshop might be an overkill.
But if you're thinking of doing some dynamically enhanced structure changes to the composition, you might consider a more long-term investment, such as photoshop.
But before all of that... you should consider the amount of time you're willing to invest into learning this application.
For example, a few months ago I decided to take some panoramic shots. I was inspired to do so when I was going through some old photographs I took in college.
I, however, didn't know how interested I was going to be in taking photographs again, so I borrowed my friend's camera to test the waters.
(do you have a friend who owned a program like photoshop? maybe you could see the program first hand to see if it's what you need.)
I took a few shots and had them scanned for me at work. I used an instant panoramic camrea. Nothing special, but I knew I could enhance the photos in photoshop. I am not an expert photographer, I know enough to get a quality shot, but I am very strong in photoshop so I knew I could make up for any lack of skills in taking photos.
Maybe it's the other way around for you? Maybe you don't need photoshop, your skills in taking pictures might be your strong point. In that case, you should consider something like VisualQuickStart, or another one of apps recommneded above, or down-under, depending on how you look at it.
(Sorry couldn't make it the whole posting with out an aussie joke, I love you guys!)
By the way, if you're interested in seeing the results of my little test you can view them
here.