I'm a non-gun person, not against them, just that I've never been around them. I'm only familiar with the HK brand (and honestly, I am uncertain on how to properly pronounce the name) from either video games or through friends' comments. My impression of them is something modern, something sexy, and more technologically involved.
On the motorcycle side, I'm also relatively ignorant, only a new rider, and on my second bike. First a Bonnie and now a Sprint ST. Choppers have never said sexy, modern, or advanced to me. (Again, keep in mind my ignorance about bikes.) I also think that choppers have run their course with being unique.
I don't think it has to be a sportbike vs. chopper discussion, there are several other types of bikes mentioned that can be picked. The BMW is a good idea, the Scrambler style is a good idea, or even a sportbike can work. Depends on who the target audience is, I guess. Here are links to pics that a friend took of a bike at Sportbike NW.
Pic 1
Pic 2
(Safe for work, hosted by photobucket, but not my pics, and they are large pics, so I didn't want to display them directly.)