For the most part the cookie cutter talent specs out there work well for us in regards to PvP and PvE with a few minor tweaks.
For the classes I've played both of these have worked very well

Elemental Shaman - 40 Ele / 21 Resto
can switch out the instant cast talent for 3% crit /hit totem per Shaman = 15% crit/hit with 5 if you go full PvE

Mage - 33 Arcane / 28 Fire

Provides instant kill status through AP/PoM/Pyro, with scorch spam allowing max fire DPS and 50% bonus on crits + ignite.