Should I buy a keyword i rank #1 for?

Title says it all.
Not only do i rank #1 for the keyword, but I have "related links" within the search as well…so im really dominating #1. Is it worth it to buy the keyword as well?
I have been buying the keyword already for months now…and it is one of my best performing keywords in terms of # of clicks and CTR.

See original post by mberman84