In that price range it is hard to beat the Nikon Monarch 5 or Monarch 7. I think the 5 is the big bargain of the Nikon line, but the 7 is well priced for HD binoculars. The 7 usually runs closer to $500 but the 10x42 is on sale for about $420.
http://www.cabelas.com/product/Shoot...3Bcat104217480
If I had $600 to spend it would be on a pair of Leupold McKinley HD.