I hate playing with mains voltage levels. Even if you survive death by electrocution, the ever present potential for fire is the last thing on your mind as you are hurled backwards, heart racing, body trembling. Rod Elliott, one of the few people on the net who I trust for advice on mains related projects, has this to say about thermistors in soft-start circuits:

Many people like the idea of using NTC (negative temperature coefficient) thermistors for inrush limiting, with many claiming that no additional circuitry is needed. In a word, DON'T.
He goes on to explain what you should do... http://sound.westhost.com/project39.htm

Enjoy.