For practical everyday use, by far the best thing I have ever used is the "Wind Protractor", which hardly anyone seems to use!
It doesn't have the mathematical functions of a whizz wheel, but it makes all your heading / time calculations unbelievably simple, is unbreakable, has no moving parts, and can be used in flight easily.
I would post a link to a picture of it, but it might get zapped! But if you search for "wind protractor" on the web site of any well known pilot shop, you should find it!
