I used to feel like this, until I saw Simon Peyton Jones use Comic Sans for a slide deck on Haskell and decided this was a such a petty, knee-jerk reaction to something as superficial as font-choice. At this point, I'd almost choose Comic Sans on purpose for my own presentations, just to weed out and troll the people who aren't paying attention to what matters.

http://research.microsoft.com/en-us/um/people/simonpj/papers...

edited to add: Dug up an actual comment from SPJ on this, I hadn't realized he uses Comic Sans for all his talks:

http://www.reddit.com/r/haskell/comments/1bd1ia/spj_and_comi...