Adobe's Photoshop is or should be on your computer if you are a photographer. Sure, you could use other image editing programs that may just do it for you, but after I bought Photoshop CS3, there simply was no turning back.
But Photoshop by itself isn't going to get you too far if you don't use the program's ability to automate through programmable actions what you need to do to enhance all your images. You could, if time is your friend, sit and figure out all the actions you will need or outsource that work and buy the actions from people who simply do a great job.
Doug and Chenin Boutwell are a husband-wife wedding, portrait (and now even commercial) photography team who has produced a pack of actions they call Totally Rad (the name is perhaps a nod to where they live in Orange County). I bought their actions early on and simply couldn't do without them. What's particularly important to me is that their actions creates a separate layer above the image you are working on. Accessing this layer allows one much greater access to tweak it to one's own liking. That is, while some actions flatten your file and you have to just accept what is given to you, Doug and Chenin's Totally Rad Actions give you the freedom to make your images look like your own creation, not someone else's interpretation.
Doug has recently launched a series of online video tutorials on how to best exploit his actions. Here are the first three:
Action Basics – Mix & Match Actions – Layers and Layer Masks
Would it help to buy the action pack as you follow along? Sure. Do I get anything for mentioning the actions here? Nope.
Here is Doug's blog where you can learn more.