I own a 4x-16x-40mm Elite 4200 and it's a great scope. Bushnell also has an Elite 3200 in 6x-18x, I think, which is in the magnification range you are looking. Nikon also has a similar range.
Both the Elite 4200s and Nikon Monarchs are in or under the $450 range you are talking about.
Zachary