I've owned and tried a lot of binoculars, finally settling on Zeiss Victory FL 8x42. They are utterly fantastic but if bought new the price tag has four digits.
I'd suggest you go to a decent shop and try as many as you can. It would also be worth trying a high end pair of Zeiss/Leica/swarovskis just for comparison purposes.
Most stalkers and naturalists use 8x42 roof prisms. You could use 8x32: they will be lighter and just as good in daylight. But the best opportunities for wildlife watching are dawn and dusk, so I would suggest 8x42 as the image will be noticeably brighter. If you have a lot of hand shake 7x42 will feel steadier.
I would advise anyone who is even slightly serious about things to spend at least £100 if buying new. At this price point you can get Japanese or Chinese 8x42 roof prisms with good multilayer coating on every optical surface (not just the ones you can see), waterproofing, rubber armour, nitrogen filling, and phase correction coating on the prisms. Phase correction makes a big difference to roof prism binoculars (Porro prism binos don't need it).
I hesitate to recommend particular models. I have a pair of Helios AM6 which is only slightly above your budget and go a best buy in one of the magazines. Japanese and very compact.
Or you could consider the Hawke Frontiers, reviews are generally good, with Swarovski styling but the periphery of the image is a little soft:
http://www.birdwatching.co.uk/Birding-gear/Birdwatching-Binoculars/Hawke-Frontier-PC-8x42
When testing, see what the field of view is like (ie how wide angle are they). The image should be razor sharp in the center, at this price point it will be a little less sharp at the periphery.
If you can, try and look at the edge of a building or mountain against a bright sky. You'll see a slight purple fringe due to chromatic aberration, and it affects the viewing if looking at a bird against a bright sky. You can reduce this with fluorite/ED glass, but that costs more.
Another option is the porro prism type. Bulkier, unfashionable (and therefore cheaper) and not easily made waterproof.
Used binos can be good value.
Good mid range brands include Steiner Minox Kahles Optolyth and Meopta. The higher end of Nikon Hawke and Opticron are also good. Strathspey seem to have a good reputation too.
I like Russian optics, the Komz above are very good. Most Russian glass has a slight yellow cast to improve contrast. i like this, some people don't.
Est German Zeiss is also good for porro binos but you need te later multilayer coating, watch out for Japanese fakes (you can tell by the serial number) and avoid pre 1990 roof prisms, even from West German Zeiss, as phase coating wasn't invented then.
One last possibilty is the image stabilised Canon binos; the cheapest one being over £200. Tried these against my Zeiss FLs on a sunny day. Hand held, I got better resolution with the Canons because of the image stabilisation, which was a shock. Then I leant against a tree for support, and without handshake the Zeiss optics won again. But I was quite impressed with image stabilisation!