The best loose cast off I've found is the Icelandic Cast Off from Cap Sease's book Cast On, Bind off.
BTW: Here in Canada we often use the term cast off instead of bind off.
I recently used this technique on a triangle scarf which is edged in rib. When I compared to several other cast offs this one allowed the rib to spread the most at the bottom edge. This is a perfect example of why I like to have many techniques in my skill set tool box. Most projects that end in rib would not benefit from a loose cast off but in the case of this top down triangle it worked beautifully! The pattern will be published soon.
Cast off with the Icelandic Cast Off as follows:
* with yarn held at back, insert tip of right needle into first stitch on left needle purlwise and catch the right side of the second stitch. Pull second stitch through first stitch and knit it, slipping both stitches off the needle. Slip the stitch on right needle purlwise to left needle. Repeat from * until all stitches have been cast off. Break yarn and pull tail through final loop to secure.
For a video tutorial of the Icelandic Cast Off go here http://www.youtube.com/watch?v=XSl13_gHlT0