Perhaps the biggest reason behind Newt's popularity is that despite his flaws, he's recognized as being extremely bright, and excels in the world of ideas. And it is conservatives who are valuing that. So how can so many conservatiuves like a guy who is clearly an intellectual if they hate intellectuals?
The answer is that what conservatives dislike and mistrust are those left-wing intellectuals who believe they are smart enough to tell other people how to live their lives. Someone who considers themselves your intellectual equal or lesser isn't going to tell you that they could live your life better than you could. But intellectuals who think regular people aren't competent enough to win their own lives? Oh yeah, we conservatives despise them.
True, but there is definitely a strain of Republicans, who are probably all supporting Santorum, who either don't appreciate or value Newt's intellect, but have a hostility to it. These people usually have trouble stringing a complete sentence together on FR. So I think it's the same phenomenon some women have toward Sarah Palin. Some women will hate any women prettier than they are and some people will hate anyone smarter than they are. They'll spin it as saying that person is "arrogant," "talks down" to people and so forth, but it's not really about that.