Is it worth a back-end developer's time to get into web-design and HTML/CSS
ssharp: The answer could be to source it now but still learn it for the future.  The nice thing about learning the entire vertical of a platform is that you don't HAVE to rely on outside help for any part of the process.  You may still want to, but being able to do everything yourself is a definite advantage, especially when time and/or money is an issue.However, you time is best spent just learning CSS and web page layouts.  Web design and graphic design are not the same thing.  You can learn to layout web pages with limited artistic talents.  When a site may need heavier graphic elements, you're better off going with an expert.  Knowing your strengths and weaknesses is very important.The wonderful thing about the web is that its very easy to stand on the shoulders of giants.  With layouts and usability, you don't need to do your own work and testing.  Take a look at websites with great layouts and morph their ideas into your own.  Read design and usability blogs and try to determine what will be best for you.Best of luck!