Living at 7500 feet, a pressure cooker comes in pretty handy. We use ours at least twice a week.
We have one of these:
Kuhn Rikon Switzerland Products: 5 Qt Duromatic Top Model
It has a spring loaded device that holds the pressure. No rattletop means no hissing and other noise ('till you get to a high enough pressure - then it gently releases).
The foodie scene's done some pretty exhaustive testing - turns out that by not continuously releasing steam it preserves the flavors better.
We love ours, but since it was made by Swiss elves it was kind of pricey. I've seen it on Amazon for ~$170 though.