Glaceon, GLACEON ALL THE WAY!!!!!! I love Glaceon!! (bad pun, watch out) It's so cool! Blizzard+Glaceon+Hail=WORLD DOMINATION!!! Providing you have an epic Empoleon in reserve. (strange, I like polar Pokemon)
Mt favorite eeveelution is definitely Espeon. That Pokemon has such a high special attack that paired with the amazing defense of Umbreon, the two make a spectacular team. They've led me to success numerous times in Pokemon Colosseum. Also, Espeon's psychic type means it is super effective against several very common types such as fighting. Last but certainly not least, the Pokemon learns a great array of moves.