The talk I gave as part of php|symphony was a big hit. I got more positive feedback from that talk than any of the talks I've given in the past. I think it's due to a combination of the refinements I've made in the way I present this topic (PHP security) and the fact that I've switched to using Keynote for all of my talks now. Having great content is important, but having it look great doesn't hurt.
For those that missed it, there is a repeat of Mastering PHP Security on Wed, 06 Apr. If you sign up by Thu, 31 Mar, it's only $40. Not a bad deal. :-)