A few things that I find out recently.
The second number in the main spec is usually more important than the first one, eg 8x20, 7x42 etc
First one is magnification, and they are all mostly around 7x, 8x, 10x that kind of range. Higher does not automatically mean better detail as it also means shake is more magnified, and lower is certainly easier to use.
The second number is the brightness and there is a huge difference between, say, a pair of pocket binos 8x20 and proper 8x40. Apart from brightness, pocket binos are harder to line up quickly, especially in low light when your pupils are larger.
For specacle wearers, you need a 'high eye point' and the design of the eyepiece becomes more important.
I bought two pairs of these Helios Mistral WP4 8x42 Roof Prism for £99.
http://www.telescopes-binoculars.co.uk/acatalog/Helios_binoculars.html There are loads of similar out there, but these seem good enough for occasional use. Smallish, bright, close focusing and easy eyepiece adjustment which is handy if you're swapping between spectacle and non spectacle wearers.
If you use them for a long time you begin to notice a bit of colour fringing but you'll have to pay double or treble the cost to get anything significantly better.
Best binos I've ever used are the Canon IS image stabilised ones, but they cost a bit.
