Definately better to get right in the camera first, any attempt to recover exposure, be it in raw or otherwise will degrade the image quality or introduce noise, just less so in Raw. The histogram is good for checking you haven't blown or clipped, but it only shows the RGB average, not per channel. I've had exposures, particuarly of sunsets, where the histogram has been fine, but when you open the image later you find it's blown the highlights on the red channel.
You have to look at the histogram in relation to what you are seeing through the lens, a subject that contains mostly dark tones should have the histogram sloping left to right, otherwise you'll have washed out dark tones. the same works the other way. so it is possible to screw the exposure and still have the histogram within no clipping at either end.
I think what janices is getting at, is that she wants to be able to get it right first time, not have to shoot, check and re-shoot by using the histogram. Spot metering will definately allow you to do that.
Having said that though, I tend to use the evaluative metering most of the time and just bracket. Seems to work ok ish most of the time.
Dunno if any of that helps or if I'm just, as I suspect, shooting off down the wrong path!