The Vanguard 8x42 Spirit ED Binocular is their lightest roof prism model with ED glass lenses and full multicoating; the rubber armored housing comes in at an impressive ~1.3 lbs (600g), but doesn't skimp at all upon the optics. This is the choice for someone who values low weight and high optical quality over a more metal-based housing which weighs more but can be knocked around a bit.
Unlike a hunter's binocular, Vanguard has given the Spirit multicoatings which target the green color spectrum, for enhanced nature observation. The waterproof and fogproof Spirit has moisture-dispersing external coatings which help to shed precipitation quickly.
The 8x42 configuration is the most popular 'classic' choice for those wanting to own a single full size binocular. Most people can comfortably hold an 8x power unit for extended periods without fatigue; many cannot easily keep a 10x binocular steady. The 8x42 also provides a wider field of view than 10x42s, allowing an easier time of keeping fast-moving subjects in your vision.