JotForm.com is GREAT! I've been using it for years and it keeps getting better. The whole thing is drag and drop and you simply add a line of code in a wordpress page or post or other site and the form appears. When you change the form it updates on your site. I use it all the time.

I've tried LOTS of options, but never had one work so well. It's one of the few services that simply works the way it is supposed to so I keep using it.

Also, Zapier (which I haven't used as much) links your forms to other places you need data.

Here are some sample jotforms:

http://mikemoyer.com/contact-mike/
http://www.slicingpie.com/feedback/
http://www.34701.org/fall2014/last-class/