^RobertWalpole, I agree: SLC is looking awesome. I can't wait until the next time I'm able to visit!
As to your question, I'm not a Utah resident, but this may be of help:
http://en.wikipedia.org/wiki/Salt_La...y#Demographics
Specifically, less than 50% of the residents of Salt Lake City proper are LDS. They may still be a majority in the county, though. They are 62% of the population of the whole state. SLC has some pretty strong non-Mormon communities.
Also, I've never heard of stopping someone in the street to ask about their ancestry, but I'm a Southern California Mormon, so maybe it's different in Utah...
We like to make fun of Utah Mormons, sometimes...
Mormons do a lot of genealogy work, for specific doctrinal reasons, but usually only for family. I imagine that sort of thing is born out of honest curiosity, not any sort of racial prejudice.