I ran across this forum a few weeks ago, and have been enjoying it since. Time to go ahead and introduce myself.
I'm a Dennis collector from way back (since about 1968), collecting the strips, books, and the comic books. I have a near-complete Dennis comic book collection (for instance, of the main title, I'm just missing #2, 4, 70, 72, 78, 100, 142, and 143), but I still haven't gotten around to using eBay to finish it off. While I definitely prefer the Wiseman stuff, I still like it all. I also don't believe in slabbing comics; only reading them. I don't have many old strips; just one small collection of 50s stuff I bought; otherwise, just stuff I've saved since 1969 or so. I'm looking forward to the new Complete Dennis book series.
As my contribution, I'm adding an attachment that I found on some auction (probably Yahoo) about a year ago: a Dennis the Menace ad for A&W Root Beer, from 1966. I used to go to a similar A&W in Owego, New York about that time when I was a kid. I recently went to a similar one in Modesto, California (apparently it was used for the drive in restaurant in the American Graffiti movie).