Occasionally I wander about with my 70-200mm lens, and a somewhat elevated ISO set in the 5D MkII, and pick up a few portraits that are acceptable (to me).
I look for available lighting situations that (mostly) produce flattering results - although occasionally I like to enhance the weatherbeaten faces of old folk.
I rarely use a short focal length lens, and have trouble producing the style of image that I like when working close to the subject. I find that perspective distortion with these lenses leads to too many unflattering images. However the short lenses certainly have their place in this type of photograph... but at this stage, they're not for me!