Jetpack contact forms are nice and easy, while Contact From 7 provides more robust options and Gravity Forms is for those that wan to go pro. All of these are great options for WordPress users, but Balloon has released a contact form system that works different than all of these (and works on non-WordPress sites as well).
Check it out:
Balloon Contact Forms
I haven’t seen a contact this good looking and this cool for quite a while. When the user clicks on your “Contact” button, the contact form slides in from the left–much like the notification system in OS X Lion.
You can easily setup your Balloon forms in their online form:
Make the changes you like, and then embed the code in your WordPress template files or whatever you may be running for your website.
I did find the demo to run a little slower than I would like in Safari, but all in all, I really dig the effect and how it all works. Pricing is as follows:
Free, includes one string (contact form), has branding
$3/month, includes ten strings, branding removed
$6/month, unlimited strings, branding removed
I like their pricing structure, but I would be more impressed with this if I had more styling options.
Learn more, give it a try and get your free string from Balloon!