I use Survey Monkey, too.
Whats nice about it is that you can create the survey to require an answer or make the answer optional as well as simply posting the link to the survey on a website so that folks who's email addresses you don't have can still reply.
I usually get a really good response to my surveys (over 75%).
Keep the questions short and give folks the opportunity to select more than one answer (if applicable) and an area to write out additional comments. I don't always get everyone to give additional comments, but the comments that I have received have been invaluable.
I just used SurveyMonkey.com It is free up to 10 questions and what is great is that in collects and analyzed the data for you. Also, no paper to use! Win win all the way around!!
