I also agree it is a good idea to talk to the guys at Bintel. Also I believe an 8x42 will make a better all-rounder than an 8x56.
Binoculars with 7mm exit pupils such as 7x50, 8x56, 9x63, 10x70 etc are specialist instruments best suited for marine, low light hunting use or astronomy from a very dark site. They can work very well in the daytime too but as your eyepupil will not be opening much more than 3-4mm in the daytime a lot of the light is not being used.
Binoculars with exit pupils around 4-5mm are more suited for general use. This includes the following;
8x30 Light and compact, wide field of view, Excellent for daytime use and OK for basic astronomy such as craters of the moon, large bright clusters.
8x40 As above but a little bit brighter, a little bit heavier and a slightly smaller field of view.
10x40 Better for astronomy but with the added magnification can be more difficult to hold steady without practice.
10x50 Great for hand held astronomy and good for everything else just a bit heavier and bulkier to lug around.
Here are some links that might be useful.
http://www.holgermerlitz.de/wisdoms.html
http://www.holgermerlitz.de/profile.html
http://binocularsky.com/index.php
http://www.birdforum.net/forumdisplay.php?f=112
http://www.allbinos.com/
http://www.cloudynights.com/ubbthrea...ard/binoculars