Rich survey plugin?

Hi there!

I’m designing a website that collects personal data of people from my home country (like location, age, sex, world views etc.) and their speech habits (eg. choice of words) in order to connect them and map out the dialects of my home country. The collected data should be easy to retrieve and analyze.

I’d like to ask for few tips:
1. In order to disable multiple voting, it seems the best way is to require registration (however that may seem like too much effort and may deter many visitors). Do you guys have any suggestions?
2. Haven’t really tinkered with survey-plugins; I need one the that is flexible, has many options and neatly records the data in the database (preferably in the format I’d tell him to). If it could include pictures, that would be of great help! (Eg. question ‘How do you call this fruit?’ with a picture of an apple besides). I’d prefer surveys that do not render completely (so they would not be as taunting), rather refresh with a new question. Also, if registration would be utilized, it would be neat if the website would keep track which question last has the user answered so next time the user could simply continue (without having to enter all of his personal data again!). I’m aware of that that there is no such survey-plugin, I’m rather interested in a plugin as similar as possible, so I could tweak it according to my needs. Any suggestions?

Thanks in advance!