These are just idea starters, but below are a few presentations I think would be interesting. Readers, please feel free to ad to the list in comments (you might find the presentation at WordCamp as a result). And if you see something here you can present, please submit a proposal!
For Designers
Utilizing Webfonts with WordPress (Google webfonts, Typekit, fonts.com)
Building a Responsive Theme
Mobile/iPad Theme Development
Learning to Use Conditional Tags
Integrating jQuery Plugins that Aren’t WordPress Plugins
For Developers
Everything You Ever Wanted to Know about Custom Taxonomies
Building a Simple Plugin that [does something cool]
WordPress as an Application Platform
WordPress Queries
For Publishers/Users
Tags and Categories: when and why one or the other
Plugins that Enhance Writing and Editing
Easy-to-Manage Gallery Options
How to…
