there is an actual right answer to this though, let me explain.
That one guy does have a point, that it matters how they are raised but...
....if all of them were at the top of there ability, then kyogre would be the best one. It is only because kygre can use such great moves.
It can defend about almost anything with taught and learned moves, and its stats at its top are better than groudon. Ive been in a long conversation about this, check out all the "rate my teams" type boards on ruby message board. It will show you why kyogre is the most all around better pokemon.
Also deoxys's stats aren't al that great, especially jirachu.
but personaly, I think mew, jirachi, and deoxys (attack form) is the coolest.