I know, I know, you want to show the world your amazing photos. I do too!! However, as a photographer, I want my images to be shown in the best possible way. Having them printed at a big box store is great if you are in a hurry. Having them printed by your photographers professional lab, is however, the best option.
My equipment and software is specifically calibrated to my professional lab, which means what I see on my screen is exactly what I get back from them.
For example, the image you see here from http://lauraacton.com
shows the difference between professional labs and retail chains.
It may not seem so different to your eyes but to a photographer it is a big deal.