A collection of free graphic design resources. I'll be adding my own freebies here eventually. For now, here are some links you might find worthwhile.

Web design resources

Open Web Design
Some nice free web templates submitted by various designers.
Colour Lovers
Browse user submitted color schemes to get ideas for your next project.
Typetester
Test out different fonts to see how they look on screen.
W3Schools html editor
View samples of html code and try them out yourself in your browser. A great way to practice html/css.
CSS Zen Garden
A collection of CSS based designs all using the same HTML file. Some incredible work can be seen here.

Photoshop resources

Free Photoshop brushes
The most comprehensive list of free Phostoshop brush sites I have seen.
Free Photoshop plugins
Another nice list of Photoshop plugins.

Illustrator resources

Mameworld vector files
A nice collection of AI and EPS files of classic arcade characters. These are not intended for commercial projects, but you can download and study some great illustrations here.
About.com Illustrator Freebies
Illustrator freebies from about.com.
Illustrator Techniques Forum
Some really solid advice to be found here.