www.getrichslowly.org/images/GRS/BMF-handout.pdf
I found this really interesting. It's a formula for managing money. Not a budget. Basically, the authors say you should aim for 50, 30, 20. No more than 50% of your income on needs, 30% on wants and 20% on savings.
I applied it to my finances and I am sadly out of wack.