Is it worth a back-end developer's time to get into web-design and HTML/CSS
pj: omg, this question is painful.HTML and CSS are skills that are worth your /time/.  Forget the money. You can improve your /own/ life with HTML and CSS.The more you know, the more powerful you are!Have you ever been approached by someone from the front end who said, "Man, it's hard to build this page the way I want it because the backend doesn't do XYZ?" and you look at them like, "figure it out!"You only do that because you can't relate to them.  You don't know how hard it is to do a three column layout in CSS so you blow them off and think, "It's been done before go do it."But that's not the right approach. The right approach is to understand /why/ it's hard from the front-end so you can make your back-end more suitable to the front.Building complex systems is a conversation between layers. Data comes from the database, goes through the "backend" then gets displayed. At each of these levels, the more one knows about the other, the easier the dialog between the layers.So, OF COURSE it is worth a back-end developer's time to learn more about the front-end.  It's also worth a front-end developers time to learn more about the backend.YES.