Im guessing Engineer? With it you could spot betties or claymores across the map. It's really the only perk I can think of that benefits a sniper, or would it be better to not have a third perk and use that point for something else?
When life gives you a Salt lick you make Larryade -- Acadias http://tinyurl.com/acs6n3b / http://tinyurl.com/a8bhltt / http://tinyurl.com/ba6zdy8
Dexterity. Imo snipers should be moving highspeed with lightweight and a shotgun, or camping with bettys or CmoreButts'. Even with the latter: if a flak jacket or LW user runs through your defenses, the dexterity will help you pull an olympic gymnast routin with your pistol of choice.