I don't know much about aikido or judo, but I think goju ryu is an very effective martial art. I think of aikido and judo as softer arts and not as aggresive as goju ryu - but like said before, it depends on who you are. In wing chun we say: "To be kind against your attacker, is to be cruel against yourself", goju ryu is also like that. Shotokan is more a wide-stance "hit and run" sport and have a "one hit, one kill"-philosophy. Goju ryu doesn't count on that and continues attacking vital points or grappling until the opponent can't move. Goju ryu is very all-round, it contains grappling, throwing and groundwork like judo and aikido. Goju ryu also emphasizes breathing, training equipment (hojo undo) and sanchin kata, which separates it even more from the modern sportskarate. So, out of those arts I would go for Goju ryu..