Cheap(ish) digital hydrometer. A little bit out of my price range still, but seems like a useful tool. Directly measures ABV and sugar content to eliminate all guesswork. Look at their video to see how it works.
I would love to have one of these; I have a hard time reading my OG when making a beer that is foamy and not very clear. Which makes it hard to guess what my final ABV is. Someday I will be rich and totally buy one.