One strat used by many Protoss players is to usually base their attack on Dragoons. This strategy requires a fair amount of gas to pull off, so most all of your expansions should have a vespene geyser. 3 gateways or more will accomodate the new build rate of the dragoons to allow the player to pump out dragoons at a nice rate.
This strategy is good for any opponent who uses mostly an attack based on level ground or from the air. Though the dragoon can fire upwards, it usually is not a good choice for a map with many cliffs and high areas. Dragoons are definitly the choice for island maps since they can counter most all units. The drawbacks to this attack is the vulnerability of the dragoons at close range. Their cool down rate is medium so it takes a while before it can fire again, so when facing zerglings or a group of zealots, the dragoon is really open to major attacks. Mass
Dragoons are also very succeptible to PSI storm and reaver assualts from opposing forces which makes this strat a risky choice. Your best bet is to keep at least some zealots wth your force usually in a 1 to 2, or 1 to 3 ratio (1 zealot per every 2 or 3 dragoons), this will allow for great flexability in your attack and provide better cover for your dragoons to do their job, much like the Muta/zergling method.(Mutas attack from the air, while the lings assualt and draw fire from the ground; in conjugate, the Zealots attack and draw fire away from the dragoons while the drags do heavy damage from the rear.=)
