Nowadays I am a big fan of jQuery. Not only has it simplified the syntax, but it also almost completely removed the need to think about browser portability issues. I've written a few small jQuery plugins and naturally they are released under a liberal open source license.
Of course I am familiar with HTML5 and CSS (including CSS3). I have also been working on my design skills the past few years, and my photoshopping skills, but I make no claims to be a professional graphic designer.