Hey Dave

6 sided poly is a definite no mate.

5 sided - yeah this is still an issue with me although, its okay to do. I've asked Steve Stahlberg about this as I was concerned about 5's arising on a Head models' cheek and therefore what would happen with the deformation? Stahlberg said he didnt have any probs with it and showed me some examples of his character with some seriously cool facial expressions/shapes. So...

But saying this, personally I wouldnt go crazy with 5's especially around deformable areas, just incase it gives you hassle on the rig, but if its in the right place and the edge/vert is terminated correctly then do it, but keep them to a minimum. But bear in mind if you are doing Subs to poly then it will convert to a four sided at the end anyway and just for good measure when you render, Maya tessellates again to tri's!
Francisco Cortina did those Final Fantasy characters with a few 5's but they were terminated in the right places.

Thanks as always

Kind regards
Jay