i would say zerg, mainly because ov's can carry men, speed upgrade, site upgrade, and you start off with one in the beginning of the game.They are also very cheap, costing only 100 minerals. ALSO, they have 200 hp (i think) Tanks and reavers and guardians can own cannons very fast, and observers only have like 60 life or sumtin. Scan-sweep is perhaps the best detector in the game, so terran comes in second. Cannon abusers just annoy the hell out of me, beacuse they think they r so cool untill you fly around them and destroy your base. Protoss defenitly comes in last, because basicaly all of their units including detecters suck besdies Temp and zealots.