What's the best subject line to hire senior developers?

I've got an ad up on StackOverflow right now with a subject of "Senior Developer - great team, great work environment, incredible challenges". I worry that this is too vague.

However, a subject of "Senior enterprise developer - C# (server) and javascript (browser)" is incredibly boring.

I also thought of "The most challenging programming you'll ever love." But I worry that will be viewed as arrogant (although I think it's a fair statement).

So...

What's the best subject line to get really good developers to send us their resume?

(The job's at http://careers.stackoverflow.com/jobs/60810/senior-developer-great-team-great-work-windward-studios?a=1cabOsh9K if you want more context.)