The Fine Art of Web Page Designs
The CSS Zen Garden shows the beauty of web page design, displaying the same content with different formatting and graphics.
Start with one of the links along the right hand side.
This collection of resources includes 100's of background images, web icons, and tutorials on everything from how to use Google Analytics to text effects.
Charles Kelly created the Guidelines for Designing a Good Web Site for ESL Students. While some points are specifically aimed at ESL teachers, the suggestions can apply to all web sites.
The design of Web pages has been elevated to a fine art very quickly. Since such designs are wonderful training grounds for the graphically talented in your classes, learning about standards from the get-go will help them. (Standards do not equal standardization.)