Here are 13 I can think of (with the help of Twitter):
Christianity is only for those (more traditional folk) who find it easy to 'have faith'
Faith is a bold leap into the unknown - believing something you don't think is true
Our (only) warrant for morality is being commanded by a threatening celestial authority
Our motivation to worship is fear of burning if we don't
We believe God created the world as it appears today (full of deformity, disaster and death)
Science rules out faith
God is a philosophical idea - like the concept of infinity
Jesus is, narrowly, the exclusive dispenser of something else called 'heaven'
Christians want the world to behave
Christians think of themselves as superior to non-Christians
Christians fear (and kill) joy. They deny themselves now so they'll get heaven later
Christians are intellectually dim and emotionally shallow
Christians fear sex/sexuality and hate the LGBT community with a knee-jerk 'yuck' reaction
(Of course many of these 'misconceptions' are completely understandable, given how Christians behave and speak in the world.)
What would you add?
One of these days, I'll get around to addressing these...