Cascading Style Sheets (CSS):
I'm gradually getting more and more into design using CSS.
I love the idea of being able to have one set of content and be able to render it in many different ways. See www.csszengarden.com for examples.
It's so versatile and you have the ability to present the information in different ways for people viewing using different mediums too.
Here's an example of a little CSS project that I set myself. CSS Redition
I wanted to recreate a logo using as little images as possible mostly using CSS to form the shapes instead.
I chose to try and recreate this piece by an [deviant]artist that I watch with great awe Vigi's Original Logo
If you look at the code of this page you'll see that only the V6 typeface and the photo (I believe of the artist herself) are images the rest is just empty <div> tags which are coloured, sized and positioned as required to recreate this work.
Please pay the artist's page a visit to show your appreciation of her work, and take a look at her gallery too, she makes such bright pictures, very joyful
In time I may submit a CSS design to CSS Zen Garden's site to add to their vast collection, which is a great source for ideas and examples of where CSS can take you.