You get one guess as to the Pokemon in my top six xDD
Espeon - Fast and powerful. May whoever said Espeon's only good use is as a Baton Passer suffer the wrath of its Psychic.
Umbreon - Yes, I know it's not too great, but I love it anyway =)
Jolteon - Sixth fastest Pokemon there is, and with great Special Attack to boot.
Leafeon - Just because I love grass types, and it has good Attack and Defense and decent speed.
Glaceon - Gorgeous (especially the shiny ones) and has awesome special attack.
Vaporeon - Great HP and Special Attack, and water types are generally great assets to any team.
Flareon... is the one Eeveelution I'll have no trouble leaving in the PC. Anyways, other than those six above:
Ninjask, Scyther, Dragonite, Ninetails, Arcanine, Crobat, Swellow, Staraptor, Gengar, Froslass, and Torterra.