Pokemon X

Pick Ampharos for an Electric-type, or at least until you get Raikou. Plusle is crap despite being a freebie (as in "no need to purify it").

-Espeon (It's Sp. Attack decimates everything.)
-Ampharos (Same as Espeon, can also set up Light Screen)
-Suicune/Entei/Raikou (Depending on your team pick one.)
-Feraligatr/Typholosion/Meganium (Depending on your team pick one.)
-Flygon
-Medicham/Hairyama (Pure Power is such a great ability on Medicham.)

^That's a pretty good. There are a couple of better choices, but you get them so late in-game that they aren't worth listing.