The 'optimum' exposure depends a lot of things and a most books etc relating to film are way out of date. Digital is very different to film.
With digital, the best exposure depends on whether you're shooting JPEGs or post processing from Raw. In both cases, chimping the LCD and histogram, with blinkies enabled, is far more accurate than any metering method. With Raw, you can push the histogram quite a lot further to the right as Chaz says, but that will usually give you an over exposed JPEG so you need to pull it back down again in post, where you will then see more shadow detail.
Basically what I do is meter using evaluative/matrix which will always get you close even if not perfect. Then chimp and tweak to taste, paying close attention to the flashing blinkies when pushing to the right of the histogram.