I am glad you added the last line of your email cause I was seriously
thinking this was a joke ;)
I would not base your decision on megapixels cause unless you are
regularly going to be making 16x24 or bigger prints either one will be
great. As a matter of fact I have some 20x30s printed from my 20D
(8mp) that are really great looking prints. more about the lens than
the camera I am afraid.
As for spot metering... you have a histogram that will tell you all
about your exposure right on the back of the camera as soon as you
take it. you can take a quick look and see if you need to make
adjustments. I never use the spot meter. I shoot all manual and keep
an eye on the histograms.
If you are going to want any speed at all you have to rule out the xti
on that account. It is SLOW. the 30D is a very responsive camera and
shoots I think 5fps which is pretty fast. Camera operation is faster
and in my opinion better in the 20-40D series than the rebel line. I
think it is more intuitive and better setup in the menus and stuff.
I think your decision may end up depending on your use probably more
than anything. if you are using it casually and you are going to
shoot like you do with film then I think the xti would be fine and it
would save you a bunch up front. It makes great images. On the other
hand if you want a camera for weddings and kids portraits I think you
need to get the 30 or 40D (the 40D is such a great camera I cant say
enough about it).
Matt
PS. I have a 20D and a 40D if you want to get together and check them
out sometime. I am pretty sure the 30D is just like the 20D with a
bigger screen.
--
Matt Dunmore
www.mattdunmorephotography.com