The ghost is another all around unit it is much like the high templar what you need to do is get the ocular implent which will let them attack gaurdians from in your bunker. Neat trick and also if you can get the lockdown and cloak and more energy. you know all the upgrades you can use them to freeze reavers carriers batlecruisers and almost any mechanical unit in ther tracks. while they are not able to move or attck all you have to do is sit there going of on them. Then you can also take them over and nuke your opponits base these all around attackers are not very strong but ther spells can make up for that.

CreepColony's Opinion: Um...Ghosts are definetly not used as attackers in defense. They are mostly used for lockdown against Battlecruisers and Carriers. A really good use of a ghost is to find where your enemy is storing his army of mechanical units, and lockdown all of them. Then nuke that place to finish them off!
By the way, this is like a long tip, so i'll give it 3 points for the contest.