Umbreon is a support pokemon for the most part. It did well as an annoyer in 3rd gen but with powerful fighting moves like Closecombat and Focus Punch on many teams, It really won't get much annoying done anymore. These days, I personally like the curse-breon and taunt-breon. Punishment's personally met my Umbreon on wifi so he knows how effective this guy is.
Umbreon@leftover
ability:Synchronize
nature:Bold
evs:252hp, 200def, 58sdef
-mean look
-moon light
-curse/taunt
-baton pass
you need a lot of defense to survive close combat when it's unavoidable. this guy can mean look an opponent, and then baton pass it to a teammate on your team that's resistent to it. Very very useful. you can even choose to pass along a couple of curses too. I used to have an aracine with white herb, and 6 curses+white herb+extreme speed was a great combo and took down entire teams.