When selecting a server, I see Veteran, Regular, and Recruit. Do these designations have any in game effects or are they more like reflections of the general attitude of the server?
According to the DayZ Wiki:
Additionally, I found this forum post which relates to the proximity detection of zombies according to the difficulty level:
As far as I can tell, the proximity detection is the only difference between Recruit and Regular, while the lack of third-person and cross-hair support is the main difference in Veteran.
It is worth noting, however, that your mileage may vary depending on the server, as any of these options (third-person/crosshairs, etc.) can be disabled at any time by the server admins, allegedly.