The point of having labels is to divide your posts into categories. That way, it's easy to find and read everything you've written on a particular topic. You don't have to decide on all the labels at this point - just have a general idea of how you want to categorize your future posts. Help your readers find other posts you've written by adding a gadget that lists all your labels. I’m sure that a label gadget helps search engines crawl your site, which is a good thing indeed. Hope this helps some. This method will help you organize older posts without having to reconstruct your blog. Then when you create new page you can start fresh.