Re: Spotting scope - angled or straight?
I've used both angled and straight scopes and really like both -- in the right application.
Angled scopes are for competitive shooting and where the shooter is in a set firing position. For example, the shooter is in position to shoot and will just move his/her head far enough off the rifle to look at the scope to read the wind, to determine when the target will be in a position to be engaged or to determine if the target is sufficiently good (in some cases, you can only shoot at an animal above a certain size). The angled scope is especially useful when a shooter is in the prone position, on target and ready to fire but needs confirmation of wind or animal position. I was on an Army Reserve National Shooting team and angled scopes were used 100% by the shooters.
Straight scopes are best when used for non-shooting viewing such as spot and stalk. This allows for a very quick reposition of the scope in a rapidly changing environment by looking over the top of the scope toward the general area and then find the animal. It is almost impossible to quickly do this with an angled scope. By necessity, the shooter is not in an immediate shooting position but will have to move. (As a side note, the coaches on the Army Reserve team all used straight scopes because they were not in firing position. Also, straight scopes are used by the spotter in a two-man sniper team.)
Final analysis: for a serious hunter that has to move, get a straight scope. Mine is a Swarovski HD 80 with variable-power eye piece. The reason I use this scope is that I spot and stalk and because I need clarity to more effectively determine such things as the length of elk brow tines and horn mass from a greater distance.