I just beat the E4 and the Champion with this team:
Infernape (rock climb, flame wheel, close combat, shadow claw)
Togekiss (fly, air slash, magical leaf, aura sphere)
Gliscor (rock smash, earthquake, aerial ace, faint attack)
Dusknoir (strength, shadow punch, thunderpunch, ice punch)
Espeon (cut, psychic, grass knot, swift [traded for signal beam post e4])
Omastar (surf, waterfall, ancient power, ice beam)
I got a good LOL as I planned this team out as it has guys from a number of decks that I've run. Dusknoir & Gliscor from VanderHatter, Infernape and Omastar from Lucksack.dek. Togekiss from last year's Skittles. I think that everyone was level 52 or 53 when I started the final run.
Overall Dusknoir and Gliscor have been my MVPs. Dusknoir with Thunderpunch and Ice Punch just made Cyrus' Gyarados and Cynthia's Garchomp cry. Gliscor with Earthquake just soloed the Fire and Lighting challenges and was even my early Gyarados counter before I got Dusknoir all trained up.
To get Omastar I traded a Helix fossil from my old pearl game into this one. I've done most of the old water types to death and wanted something else new. Omastar is really the only weak link in the group and even he's not too bad as long as I don't send him into the wrong matchup. He OHKOs all sorts of stuff with surf. I had to get rid of Mud Shot to learn waterfall which made me sad as he had great type coverage before that.
Togekiss was a pain in the tail for most of the game, but once I got past Iron Island he was amazing.
I've been very happy with Espeon and Infernape, though neither have really been as spectacular as Dusknoir and Gliscor.