For the sake of completeness, mainly that someone else may stumble on
this thread looking for useful information...

While I was there, I talked to the manager, whom I know well
and trust, about the (apparent) noise I'm seeing with my XT.
Like most everyone else, he was incredulous, then strongly
suggested that my particular camera was defective, as his
experience was 100% the opposite.

Given that later he establishes that the store-owner's 100% good camera
and his 'bad' one behave identically, what would a normal person infer?

So, I pumped off about 30 shots, some with the built-
in Speedlite and some available light, across subjects with a
lot of detail and both light and dark backgrounds (the latter
to better pick up any inherent noise).

In other words he went looking for noise in dark areas...

1) /Both/ camera's, my "defective" one and his "working" one
showed the /same/ amount of noise at /all/ ISO from 100 to
1600 on /all/ 3 of my PCs. Naturally, no noise is readily
apparent until ISO 400 on both cameras.

Good-oh. No real surprises there.

2) Despite being careful on Programmed Auto in both flash

Oh dear. Here we go back to square one. I've never yet met a
camera/flashgun combo that had infallible auto-exposure. In
particular, and as stated MANY times, if the subject has significant
refelective areas that bounce the flash back at the sensor/s.. You
can't be 'careful' in auto mode. Manual mode, or proper flash
metering, is being careful.

some of the pics I took with the store's
camera and pics I took in my house with my own, are a stop or
2 underexposed. Please don't debate this yet, either.

When should we? It's directly relevant. Even at a single stop
underexposure, noise problems will be exaggerated, and at 400 ISO will
be by far the most significant cause. And on auto mode, he is asking
for wrongly exposed images, especially if there is anything even
remotely challenging in the subject. Like.. chrome and polished
paintwork.

The more the underexposure, the higher the noise.
Well, Duh?! I already knew that, and that explains the
extra noise I got Wednesday at the WPC Museum
- but which I've already explained I understand.

And we do too.

so far, it still looks like the medium 5.5 MP images
saved on both cameras with the highest quality
(least JPEG compression) /all/ show about the same
amount of noise.

Fine. Point being? And why not at least use Tiff files if evaluating
noise.

Suffice to say that there /is/
a problem with the Rebel XT - from my perspective.

Key words - 'from my perspective'.

Another way of saying all this is - 'I'm not prepared to put in the
effort to ensure my images are correctly exposed, even though I shoot
shiny objects in dim environments, namely cars with an on-camera flash
(yes, I'm *serious*). My images come out underexposed and noisy. It's
the equipment's fault. I can't believe that all my cameras and flashes
have this problem to a greater or lesser extent, and that no-one here
will help me. It's certainly not my technique, and don't you *dare*
suggest I'm trying to do something the wrong way. Agree with me and
I'll be your friend. Suggest anything else and get in the neck.'

Now, you can all write me off as just another
nutbag/troll/incompetant/inexperienced/closed minded/asshole
if you like.

Heavens no. Not us. Uh-uh. No way.

But, as the saying goes "I don't know anything
about art, but I know what I like."

The people who say that are BUYING the art, not creating it. I think
he missed the point of the metaphor entirely. (O: (O: (O:

Insults to me or my intelligence will be ignored.

I betcha he doesn't.....