Okay, here you go:

The water coming out of my kitchen faucet blasts out like a fire hose.
No other faucet in the house seems to have this problem. Today, I had a
plumber over for a different problem, and asked him to render an
opinion on the faucet-pressure problem.

He looked into it (I wasn't home when he did his check; the wife had
him call me), and said the pressure regulator in between the street
service and the house wasn't actually regulating the pressure -- it was
letting in 145 pounds (psi?), which is street pressure. I raised the
question as to why the other faucets in the house weren't blasting; he
says he checked, and yeah, they are all overpressured (I just don't see
it -- or, rather, feel it).

The fix, apparently, is to replace the regulator (which would seem to
make sense), and also to put some kind of "bladder," or smaller tank,
on top of my water heater, so that when water is let into the tank at a
specific pressure, and then heated (raising the pressure), it won't
blow anything out.

It's this last part especially that sounds fishy. I've never heard of
it before, never seen a water heater that has such a device, and the
"physics" doesn't ring true to me.

So, what are the expert opinions on all this here? (My wife just phoned
again, and this guy wrote on his work order that we should "turn the
water off [that's the main water supply to the house]" so as not to
risk damaging anything.)

Oh, and if anyone has any ideas on the blasting faucet, I'd appreciate
hearing those, too.

Shane