Picking the right advisors, approaching them correctly and making sure they get involved can be challenging and extremely rewarding.
Advisors can help you figure out the things you don't know you don't know - the real killer mistakes that you're not even aware you might be making. And they can give credibility to your company, open doors, and many other benefits.
Joey's article goes into some detail on how they went about recruiting their board of advisors, how they compensated them, and what they got out of it. Worth your time.