Just to clear up some things here..
SLR = Single Lens Reflex without the Reflex part of the
definition it doesn't really make sense to refer to a
camera as an SLR. The Olympus E10 and E20 fit the SLR
definition because they have a splitting prism rather than
a mirror and pentaprism viewfinder but anything with an EVF
that meters through the lens is just defined as "TTL" Through
The Lens.
It is possible to have an SLR body that could use an LCD
for a live preview but it goes completely against what an
SLR is for. If you buy a D-SLR you are buying it because
you want the absolute best quality photographs and by using
a real leaf shutter and keeping the CMOS or CCD off all the
time except when capturing the image this keeps the noise
down by eliminating excess heat created by the constant
use of the sensor.
As for metering that comes with experiance. I find that the
built in metering on my SD10 is "close" within about a half
a stop. If I wanted spot on metering I would use an external
meter before I ever took a photo. But the beauty of digital
is the ability to auto bracket and fire of a bust of images
with varying exposures. Surely one is bound to be right
Or shoot RAW and you have at least 1 stop exposure latitude
with most cameras. In RAW on my SD10 I have more than 2
stops of exposure lat.