I pack in dress pants constantly, but I always wear boxer briefs because they keep things in place and in doing so I can make my bulge unnoticeable. Be discrete about it but if you look at other men in dress pants, most of the time you'll be unable to notice any real obvious trace of their penis. I don't like the feeling of wearing boxer's, which packing, in dress pants because absolutely nothing is keeping anything in place, and thing's tend to.. wander... I've made the mistake a few times and I hate having to make my way to the bathroom just to put myself back in order enough not to offend anyone.
However, like all things, it's your choice to make. If you want to wear boxers in your dress pants, expect your bulge to be more noticeable, but do it or wear box briefs for more control over the situation. Either way, it's your choice!
But to re-answer your question, the only other type of pant's i've found to show your stuff off more is flannel pj bottoms. So yes, they do make you bulge very noticeable if not coupled with tighter underwear (boxer briefs/briefs)
A bit more of my personal opinion, take it as you will but I feel that if you are wearing dress pants, that means you are in a very formal environment and you should not be showing off your junk in any way that causes attention. You are there to do your job, not trying to lay the intern. That's just my opinion though, take it or leave it.
