Here's my opinion with scopes:

Take the price and overall quality of the gun. Divideby 1/2. That is the starting point to start looking at scopes for it.

Example
$900 - Remington 300 Ultra-Mag: Youwouldn't dare put a cheesy $49.95 BSA scope from Wal-Mart on it. So, you could safely say, that for $450, you could get a heck of a good scope for it at a bare minimum. Now if you really had the $$$$ you could also spend another $900 and get a top quality Zeiss scope for it.

Just my opinion...