Is it worth buying misspellings around your domain name?
tsally: When you have the popularity for this question to matter, and the staff to answer it, you'll have enough money to buy whatever domain your research tells you that you need.  This was the approach Dropbox took (getdropbox.com -> dropbox.com).  Delicious did it as well (switching from del.icio.us to delicious.com).  I know misspellings are a little different, but for now I say just build your business.