HTML, then CSS to go with it. Once those two are top notch, I'd move on to PHP/MySQL (I love 'em). I've basically stopped there, now I'm developing some web-apps etc, as well as a billing system for my host (sig). After that I'm not sure what to learn, I looked at JS but hate it, so I just use jQuery + Plugins for anything. For now, I'm just increasing my PHP/MySQL skillage