If you've been to a big conference in the past few years you'll have seen the name David Platt on the speaker list, and usually scheduled into the big room. Dave's superbly entertaining speaking style delivers valuable information about user interface design and genuinely meeting the needs of the folks who use the systems you're developing.
Here's an interview with Dave recorded at Tech Ed, and on the Tech Ed Europe sessions page, if you click through to page 2, you can see the one hour version of his talk.
Since Dave mentions used car salesmen in his interview, I'll share a little joke with you. What's the difference between a computer salesman and a used car salesman? The used car salesman knows when he's lying to you.