I'm surprised at how many people don't know about a feature they probably already have, found in the Web Developer plugin for Firefox. The Edit CSS lets you see your changes live as you type. I use it all the time.
You hit refresh and those changes are gone.
I see the value of this for alot of one-person development shops or front-end devs that do a lot of client design work.
Your client calls you, "Hey, this thingy here isn't lining up right"
"click. click. publish"
"refresh the page"
"ohhh....how did you do that?" (Client amazed)
But, this is---for me---a one time thing, after I've made all the changes I want and things look great. It makes the CTRL-S, Alt-Tab, Reload procedure that was originally described only need to happen once, instead of lots of times in rapid succession.