sersis

This plugin allows you to create complete surveys, publish surveys with a shortcode and view survey results in the admin backend. You can also see the statistics of your voting poll..
<h4>Features</h4>
<ul>
<li>Publish your survey on pages or posts by including a shortcode.</li>
<li>View results of your surveys (statistics) in the admin area of your WordPress site.</li>
<li>Contextual help available for many of the survey builder options</li>
<li>Export the statistics in PDF format</li>
</ul>
<h4>PRO version</h4>
You can more: 
1. Create more surveys 
2. Duplicate survey 
3. Choose whether to show the title of the survey or not for each survey 
4. Choose the size that the title must have for each survey 
5. Choose the color of the button to vote 
6. Export statistics of your surveys also in CSV and XLS format
<ul>
<li>Visit our website to download the <a href="http://www.sersis.com/wordsurvey/" rel="nofollow ugc">PRO Version</a>!</li>
</ul>

WordSurvey

Create & publish complete surveys with a few mouse clicks. All data collected remains in your control and you see the statistics in the backend.

DCoda

This plugin is only supported on PHP 5.2 or greater.
 
PollMe is an easy to use and easy to modify polling tool for WordPress. Written to be easy to use to none coders.
You can design as many polls as you wish , displaying the results as either a bar are pie chart using Google Charts you can also download the raw data into a spreadsheet. 

If you are having trouble and cannot find the answers in the <a href="http://pollme.dcoda.co.uk/help/faq/" rel="nofollow ugc">FAQ</a> you can post your support questions to the <a href="https://wordpress.org/tags/pollme" rel="ugc">WordPress Support Forum</a>
If you find PollMe useful please rate it at <a href="https://wordpress.org/extend/plugins/pollme/" rel="ugc">wordpress.org</a> and please consider making a <a href="http://contactme.dcoda.co.uk/donate/" rel="nofollow ugc">donation</a> to help us set aside more hours to maintain PollMe
PollMe is written by <a href='http://dcoda.co.uk' rel="nofollow ugc">dcoda</a>
You can check out our other plugins <a href="https://profiles.wordpress.org/users/dcoda/" rel="nofollow ugc">here</a>
If you require a custom plugin you can contact us <a href="http://dcoda.co.uk/contact/" rel="nofollow ugc">here</a> and maybe we could write it for you.
<h3>Copyright</h3>
(c) Copyright DCoda Limited, 2007 -, All Rights Reserved.
This code is released under the GPL license version 2, available here:
<a href="http://www.gnu.org/licenses/gpl.txt" rel="nofollow ugc">http://www.gnu.org/licenses/gpl.txt</a>
There are so many possibly configurations of installation the plugin can be installed on we limit testing to a PHP 5.2+ Linux platform running the latest version of WordPress at the time of release but it is released WITHOUT ANY WARRANTY; 
 without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

PollMe

An easy to modify poll system that uses Google Charts to display the results

WordSurvey vs PollMe