It depends on the builder, it depends on the owner (if it's being built).
My house didn't have a finished basement when it was built. A later owner "finished" it, and did a 3/4ths crappy job.
I think in today's real estate market, though, you're a lot more likely to see a fully finished basement.
If the basement is unfinished, it does not tally into the square footage of the house, at least for tax purposes.
I think you tend to see more finished basements in houses that have walk out basements. Mine doesn't -- it's a full-inground basement.
I wish an older home was a guarantee against shoddy construction. I've found a LOT of crap in my house that makes me thing the county inspector was having his pockets lined.
As for termites, yes, they are a problem in this area. I've known a number of people who have had termite problems in their homes, or found termite problems in properties that they're going to purchase.
Which reminds me, I need to have my property treated again. It's about time.