For hunting, when I carried a pair, it was my Leica 7 x 20Bs. Compact with roof prisms, good optics, each barrel individually focused at the aperture. I really didnt need them as most of my use was running and gunning for turkeys. Where I hunt, Im lucky to have a clear view of 75 yards. I stopped carrying them as I was bound to lose them. For marine use and truck use, I have a pair of armored Fujinon Meibo 7x50 porro prisms. They are heavy enough to kill a rhino with a head whack. For general birding or astronomy, I use a pair of lightweight Zeiss 6x42b Dialyt, roof prisms. They do a good job of gathering light despite having 70% of the aperture of 50 mm. Aperture trumps all when it comes to light gathering all things being equal. I prefer 7x, but the price was right. I had a fine pair of inexpensive Nikon 7 x 50 porros. Star images were pinpoints and they were relatively light. I traded them for the Fujinon. If I were thinking of buying another pair, itd be Swarovski regardless of size. None finer. There are some bargains on the used market. Local camera shops often carry used binoculars, but some may need collimation. In steadying binoculars of any size, anchor the binoculars against your check bones or under the eye sockets with your thumbs. If anyone is interested in a good discussion of exit pupil size and optics, take a look at:
http://www.skyandtelescope.com/astronomy-equipment/a-pupil-primer/
