Glaceon's use would be rather limited (and Vaporeon can learn ice attacks too); as would be Flareon's (especially with its lousy Special attack stat and limited movepool). Umbreon is only good as a wall against other Pokémon (I assume that, regardless of stats, it would not take a bullet very well) or sneaky mindgames.
Leafeon would be my prime choice as a gardener or if I lived in a forest, but I doubt it would feel comfortable or be of much use in a city, except for ecoterrorist attacks: “long have you cut your hedges and lawns, but now the plants will cut back! Leafeon, use Leaf Blade!”
Now, it depends on how applicable the others' powers are in real life. What would Espeon's powers translate to? Could it toss about heavy loads with Psychic, mess with people's minds, and stop bullets in mid-air? I believe it has the most potential, and its powers could be applied in the most situations.
Vaporeon seems like a great all-arounder. I live by a river, so I could Surf on it to get around. Its Hydro Cannon could be used for riot dispersal, its Aurora Beam to freeze bodies of water, people, or fresh vegetables. And it has got high HP and can heal itself with Aqua Ring, so it could survive a lot of possible hazards. Heck, I could sprinkle it with a garden hose and it would heal thanks to its ability.
Jolteon would be the most lethal of the bunch, since it could stun or kill with its electricity at dazzling speeds, and probably shortcircuit electronics. But I live a peaceful life, and have no need for such violent uses. If I lived in a crisis zone, it would be my prime choice however.
All in all, I would opt either for Vaporeon or Espeon, depending mainly on the abilities of the latter.
