http://ethanmarcotte.com/

He has written an amazing book on Responsive Design featured on A Book Apart (http://www.abookapart.com/products/responsive-web-design).

More about Ethan Marcotte (http://aneventapart.com/speakers/ethanmarcotte/).

Seeing how these guys developed some of the technologies bigger Drupal sites like the ones we help create, here are a few suggestions:

• John Resig: kind of surprising he never yet spoke at a Drupal event
• Peter Zaitsev or Baron Schwartz from Percona, the high-perf MySQL experts
• Luke Kanies, creator of Puppet
• Kristina Chodorow, most prolific author about MongoDB

I know the devseed guys are doing a lot of awesome mapping, nodejs and javascript in general these days. It'd be awesome to here some of their insights to the world they occupy now.

http://eaves.ca/about/

David gave an awesome and fun presentation at Pacific Northwest Drupal Summit about applying negotiation theory to the unique communication challenges that open source communities present, and how to build our tools around compensating for human nature.

David's also a huge open data person, and is an advocate of getting open source communities to provide open data about their communities' own activity, in the same way that we advocate for governments to make their data available to the public.

I'm doing a really bad job of summarizing just how awesome he is, because it's way too early. :) But particularly with all of the various "crisis" posts going around London, I think a talk on how we as an open source community can best capture and present data that helps us to work together more effectively and as better humans would be super on-topic and relevant.

Aaron is the user experience design lead for MailChimp. Aarron writes about web design for industry publications, and has even written a few books, the latest of which is Designing for Emotion to be published today, with Luke Wrobleski's book on Mobile First.

More about - http://aarronwalter.com/about/

Experienced presenter and deeply knowledgabe about Joomla, its heritage, community and ecosystem. Why not get some perspective on crisis, opportunities from someone over the fence. Joomla foundation have approached similar challenges to Drupal with very different responses. It would be fascinating to hear him speak. I know him personally so have an inside view. He has a reputation as a fabulous speaker.

Lea Verou has a long-standing passion for open web standards, especially CSS and JavaScript. She speaks at a number of the largest web development conferences and writes for leading industry publications.

lea.verou.me/about/