I would say that if you are HTML- and CSS-challenged, you could change to WP theme which approximates the look you want to have for your site and install the BP template pack plugin.
If you’re just going to run a default BP installation, i.e., just use default features, then you’re set until the time where you need a multi-DB solution for the growing number of users/blogs in your install. But if you want to customize presentation and functionality within the site, then you’d either have to learn PHP,HTML,CSS,JS,WP,BP or hire a developer to help you out.
