There are a number of poll providers who have systems available for blogs.
I personally use the Democracy plugin for WordPress (AJAX based) these days and don’t have any problems with it.
Other poll systems that you might like to try (I can’t really vouch for any of them) include:
If you’ve had experience with any of these or other blog poll tools feel free to leave your comments and recommendations below.
PS: I’ve added these blog poll tools to the blog tools page.