Quoted from ZippyThePinhead:The option of "something else" is vague to say the least. It doesn't help to determine what pin Pinsiders would like to be made. If there is "something else" you would like to be made, you are more than welcome to post it in a post...
Technically spoken, a poll like this should indeed have a 'something else'-option. Not including one implies that the given choices are the only possibilities. Which probably leads to results that are not real (people picking their first choice on the list, which doesn't necessarily have to be their actual first choice).
Simply put, the question you ask is an open one ('What music theme pin would you like to see Stern release next?'), while the answering options are limited.
You say that 'something else' would make the results more vague. That may seem so, but actually it means this: if the 'Something else'-option would get a high ranking in this poll, there is a good chance that there should have actually been more or different choices in the answering options. You can always ask people that vote for 'something else' to explain their choice in the thread. But the option should be in the poll to get valid results.
This is not anywhere intended as a bash. It's just a more technical approach to polls and voting. I like this thread. It's an interesting discussion and a good read.