Over at Point Blank SEO (you don't follow the blog - why not?!) Jon Cooper has a massive article on link building strategies. It really is a huge list of inspiring ways to gain backlinks. Links that will help your site, not crappy garbage links.
It's not a new post but for anyone who hasn't gone through it I urge you to read it - several times - and take action!
Link Building Tactics - The Complete List Point Blank SEO