Also, take it out of gear and use your brakes to stop. Brakes are a lot less expensive and difficult to replace than a clutch.
Meh, I downshift under braking all the time and the clutch was still working great when my tranny was rebuilt at 335k. Oddly enough the new clutch is acting funky... it was either slipping yesterday or I made two 3rd gear starts when I thought I was in 1st. (Which is unlikely because I've never done that before, so why would I do it twice in one day? Now it's acting fine again, grr-argh. If it's going to fail I want it to happen while there's still warranty on that rebuild.)