Flexible connectors to water heater are usually only allowed in
earthquake zones. Check with your local building inspectors to see if
they'll allow them. If they do, you want the corrugated copper lines,
not the rubber/stainless steel variety.

If you've had trouble with high water pressure, it's a real good idea
to install an expansion tank on the cold side of the water heater. In
fact, they're always a good idea since they cut down on stress to the
sides of the tank.

As for heat traps, check with the new water heater. Most models
include them from the factory. That's how they can squeak out a higher
efficiency rating.

Replacing the hot water heater...are flexible connectors any good, and
if so which are the best? The EPA recommends a "heat trap" for in and
out going water; a flexible connector, basically, with a u-bend. Is
this a good idea? The local plumbing supply store guys scoff at
anything but sweat fitting and straight copper pipes. Also, how would
I know there's any problems with water pressure? About nine years
ago, I was talked into installing a pressure regulator, and I've had
nothing but trouble since. I don't have overly high (city) water
pressure; never had trouble before with anything. The house was built
in 1989. Why shouldn't I just take it out, and that way I don't have
to install an expansion tank? Any ideas, Joe?