Apparently the human eye has a similar latitude or even a bit less to consumer-level digital sensors - about 6 or 7 stops. Yet the world
appears to us as though our eyes capture perhaps twice that much latitude. Obviously we're dealing with some pretty nifty image processing inside our overgrown crania. But for all that evolutionary magic, specular highlights remain blown even to human vision. Specular highlights put the twinkle on the chrome trim of a new car and the dance upon the face of the water in a luxury pool shot. That's what our eyes show us and that's what slick advertising shots show us, so I don't think you need to attempt the impossible.
Now when it comes to white paint - well that's more of an ... ahem ... grey area, but I think the same principle applies: if it's blown to your own vision as you take the shot, feel free to let it blow in your shot too. That glare is a cue to the contrasty nature of the original scene. An exception would be whether the details of that white painted window frame are an important element in your shot. For example: if you're doing an ad shot to sell a house, then getting the detail might outweigh getting the mood. Yet as Bill Janes rightly points out, it may not be practical to come back on an overcast day, so you may either have to choose your poison - blown highlights vs. blown shadows - or bracket then do exposure blending. Incidentally, another common example of whiteness that I keep running up against is white flowers, such as daisies.
If the D80's matrix metering doesn't cut it in contrasty light, don't forget you have the same in-camera 2.5 degree "spot" metering that Nikon has offered for many years. While not 1 degree, it should suffice to nail the exposure in most situations. And of course you can just review the shot and check the JPEG-based blinking highlight warning if you have the luxury of a bit of time before the next shot. Or you could get
really serious and spring for Sekonic's new
L-758 DR hand held. ;)
