I've done some work work in a museum textile lab, so that's definitely affected how I view my everyday laundry.
It's most important to avoid unnecessary friction and unnecessary heat, so I wash almost all my things in cold water on the gentle cycle, and generally hang them to dry. (Heat breaks down spandex, and I've found that most of my things last a lot longer when I don't put them in the dryer.)
The actual detergent I use can vary, but I prefer to avoid optical brighteners and like additives. For less sensitive things (like jeans) I'll use whatever is around - on gentle cycle, cold water. But for silks, fine woolens, etc (protein-based fibers) I use a product called Orvus, which was actually designed as a horse shampoo. (You have to have very soft water to use it, though. )
I'm probably fussier than most, but I find that it helps keep my things nice for a very long time. There are a lot of people who swear by dry-cleaning their denim to keep it from fading. It works, but I don't like the chemicals.
