Agree on the jet wash front, i made the mistake of using one, and my bonnet is now covered in long scratches!
I don't really feel the odd drive through car wash would do a huge amount of harm?
I do use them, maybe once a month at the most, along with hand car washes if i'm passing one.
I know this is far from ideal, but I do a lot of miles, and my boss likes us to keep our cars clean...
I wish I could clean it myself, but living in a first floor flat I don't really have that option - though I do make the effort to drive to my dad's when I can and give the car a proper clean myself.
On this subject, has anyone used an ARC car wash? Usually dotted around larger cities, I have used them a few times, you pay around £2, some ape of a man sprays some prewash on your wheels and gets the worst of the dirt off, then you drive in until your wheel is pulled along on a conveyer belt, after about 2 mins your car emerges gleaming! It's not perfect of course, but great if you are short on time.
As my car is leased I guess long term paint protection isn't high on my list of priorities, I'm sure it would be different if it was my own.