360GameTV has a clear & easy-to-follow guide with all of the Destiny collectibles (Dead Ghosts & Gold Chests). There are total of 62 Dead Ghosts and 20 Gold Chests in the game. Some Gold Chests are only available during Strike Missions.
For the Ghost Hunter Achievement you only need 50/62 Dead Ghosts. The 20 Chests have no achievement associated with them, but they’ll give you unique rewards.