I don't mind so cal or cali. Being a So.Cal native I Won't say Nor.Cal (no offense but it just sounds a bit white trash). It's like saying your from the 909. But it could be a beach cities thing vs everyone else.
It would be interesting to see where people determine So.Cal and Northern Cal. Personally anything above Santa Barbara could be another state.
I also don't think people from San Diego say So.Cal I think they like saying San Diego.