Jolteon is for more speed and Espeon is for more special attack. Espeon also better as a lead thanks to Magic bounce giving him the ability to reflect stealth-rock and other entry hazards.
Leafeon is by far the best even though has slightly above average speed he has awesome attack and defense and far outclasses Flareon who is the weakest eevee evolution.
Umbreon all the way he has HUGE defense and even HUGER S.def and a GREAT hp stat as well along with a variety of walling moves such as toxic, curse, payback, and moonlight and wish.
there is no real physical tank but Flareon has huge attack and great S.def but he has such an aweful moveset that all you have to work with is fire fang, iron tail, return, and curse. EDIT: Leafeon can also tank physically because of a 130 defense stat and plenty of offensive and support options.
Glaceon and Vaporeon are the way to go Glaceon for better defense and Vaporeon for more hp, Glaceon is best in a hail storm for it raises evaisevness and Vaporeon is a great switch into water attacks thanks to water absorb