I know I'm probably in the minority here, but I'd focus more on "power" than "relevancy".
Sure relevant links are great to drive traffic, but depending on your niche, they may be very difficult to get.
For me I usually focus more on power of the link (eg high pr) over relevancy.
I would take a pr5 link from an unrelated site over a pr3 link from a relevant site any day of the year.
Of course if you can get em great, but again don't let that hinder your request to find strong links.
Again I am purely speaking from a search engine ranking perspective, not things like developing a following, siphoning traffic etc.