Lol...I beat the elite four with these three:
Arcanine lvl 43
Milotic lvl 45
Gengar lvl 43
You know the first guy, Sidney, who uses dark pokemon? I beat him with only Arcanine...after about 2 or 3 Howls, I ran through all his pokemon OHKO with Extremespeed, and Overheated his Shiftry...lol that was fun XD.
Phoebe was being gay cos for some reason I couldn't Mirror Coat her Shadow Balls bak at her. And Dusclops has huge Spec def...
Glacia has blehhh as well, Overheat and Extremespeed the Glalies and THunderbolt the rest.
And Drake the "Dragon master", All I used was Milotic with Ice Beam, every single dragon he used, and he couldn't do a single thing cos even at that level my milotic was faster than all of his pokemon. And I have a feeling i either beat his Kingdra by using psychic with Gengar or Destiny bond...
The champion...was pathetic. Thunderbolt from Gengar cleaned up all his pokemon. And Whiscash was done using Giga drain
My pokemon are fully charged with full EVs in the right spots so that helped a lot.