It depends on how big your business is. If you're selling small amounts of stuff from home then pretty much any out of the box solution will do. If you're business is bigger than that I'd think about getting one built from scratch. Modern web development platforms like Ruby on Rails can give you a lot for not much investment and the site will better reflect who you are now and grow with you in the future. There are billions of web pages out there and out-of-the-box sites do tend to look & feel very samey which won't help you win customers. Bear in mind also that web 2.0 is really raising peoples expectations of what to expect from a site and again, out-of-the-box & web 2.0 don't go together.