I do think when non-Christians think negatively of Christians, they are primarily thinking of evangelicals or "born-agains".

I read somewhere that when you say "Christian", the image that pops up in people's heads is a middle-aged white man in a suit, standing on a soapbox with a Bible in one hand and American flag in the other, shouting denunciations.

Even with my insider experience, one of the first images that pops up is Young Earth Creationists and/or Left Behinders going "DIE, HERETIC!" (This comes from a Christian YahooGroup I used to be on that blew up in flamewars constantly on these two subjects -- Young Earth Creationism or Pin the Tail on The Antichrist; the constant flamewars finally killed the group. As J Vernon Magee said once on the radio, "A lot of Christians are more interested in who The Antichrist is going to be than Who Christ Is.")