I have passed on many opportunities. Without a lucid mission and vision, what is the company doing? If my heart isn't in full alignment with the organization, why am I committing a large chunk of my waking life to furthering their goals? Our dance on this earth is too short to commit your health, talent, and wisdom to something you don't believe in.
Can you share the circumstance that you're mulling over? Good paycheque, ambiguous plan?