I first came across the concept of Cascading Style Sheets in 1999, and thought it was the coolest thing ever--it reminded me of word processing back in the days of Word 2.0 for DOS (the first version of Word I used). In 2000, I started evangelizing to anyone who would listen--but nobody would. I was told that CSS was never going to take off, because the browsers would never support it. That it was too hard for most people to understand, and anyway, why was it necessary when you could do all that boldfacey stuff with HTML? I tried to tell them that XHTML was the way the web was going, and I talked about web standards all the time, but again, they told me I was wrong, and that if I really wanted to be at the forefront, I should learn Dreamweaver.
As is my habit, I assumed that if that many people (seriously, it was at least four) thought I was wrong, then maybe I was. I learned Dreamweaver, and I learned to slice-and-dice in ImageReady... and then I went in and cleaned up the code, because I couldn't believe I was TOTALLY wrong.
So here's my advice right now, to myself and to everyone else: Learn HTML5 and CSS3, because you will need to know them. Mark My Words.