Now I think I *do* need a poll :)

Aha, I've worked out a good retrospective reason why it would have been bad to create a poll for this question. It's because no matter whether I did the poll by radio buttons, tickyboxes or drop-down lists, I would have had to state the suit names somewhere in the poll text, and that could have biased the results because they'd have had to appear in some order. By just asking a bare question without naming the suits at all and encouraging people to reply without reading the rest of the post, I actually did better at avoiding bias :-)

Real life pollers actually have this problem. I can't remember any solution though other than "don't show the takee the poll", "randomise the order" (and increase the size of the sample), or "put the one you want to win first"