In the past, to run online surveys I used GoogleDocs and SurveyMonkey. One was a paid service and the other too minimalistic. LimeSurvey though is a very nice open source platform to run complex online surveys however you choose.
The list of features is quite incredible, the best ones I found were the export / import format options (including SPSS, CSV, PDF, and .xls); large possibly of question types; integration of pictures and movies in a survey; and plenty of graphics options for you to analyze results inside the platform.
I was very glad to find this platform so I can run surveys the way I want to and be sure that all of the data is kept safe with me.