I came across this poster a couple years ago at the Cool Infographics blog. I found it absolutely perfect!

 Fast, Cheap, and Good Websites are made by Unicorns and Leprechauns.

The fact is you can only pick two when looking for fast, cheap or good.  When it comes to website design, Search Engine Optimization, or Online Video, if you go for Fast, Cheap and Good you will most likely end up with none of them.