I personally think it depends on your reasoning and intentions for initially starting the business. For me it's a combination of things including "working smart, not hard"
as well as wanting many large ticket items that I wouldn't be able to have as easily in my situation. Being an audiophile and having many hobbies isn't cheap you know
Back to working smart, not hard - I think this is something very important, too many people simply work hard but not smart. This can be interpreted in many ways, some will see it as being lazy while others will see it as efficiency and getting more done in a certain amount time than someone else doing something similar. For me, it's finding a good balance between both extremes of doing lots of work and hardly working.
Focus your business around this! Help your clients work efficiently with a detailed knowledgebase and at the same time lower your support requests. Use quality server hardware and have experienced server administrators so you run into less problems. If you find yourself doing something over and over again for people, why not write an article on it? There are many little things that add up that can be done to help your business run more efficiently.
So what is success to me? Being able to "work smart, not hard" and reaping the benefits of being a business owner
Hope I didn't draw this out too long though, heh, I've thought quite a bit about what I feel is an accomplishment or success so my thoughts might be a bit hard to follow