@sallow. I got the "86", there's a pic of it in the "Show Off Your Straight Billiards" thread. I'm on my phone right now, so I can't post a pic in this thread at the moment. It's also in the "Show Off Your Petersons" thread.
For me it's any pipe with a rubber bit on it that I can clench comfortably. I do prefer billards though just because I can run a pipe cleaner though them easier with less fuss.
I smoke in my truck every day to work and back.
The only thing I would add, is that I only smoke a full-bent pipe in my car. I worry about someone rear ending me hard and sending a straight pipe into my neck.
I smoke my Peterson 317. It's a small bowl, but I have no problem dipping into my pouch to refill it one-handed, and lighting with my zippo. I always clench anyhow. I've smoked up to 5 bowls in a row in this pipe, one after another, with no ill effects.
Stanwell feather weight series comes to mind. I have a "Sixtus" hat is my pipe for flakes. Looks like this.
http://www.smokingpipes.com/pipes/new/stanwell/moreinfo.cfm?product_id=74198
I have a different point of view. I like a full bent in the car. Fits nicely in my cup holder, clenches comfortably w/o balance issues, and holds a copious amount of tobacco for long drives, since it takes me 30 minutes to an hour to get anywhere I want to go. Edwards full bents turn up on eBay often. I have an Edwards Oom Paul that I bought in the 80's, from the basket. It has a lot of fills but the Algierian briar is quite rugged and it still smokes like a charm..