Totem dropping in pvp is always situational. Part of mastering the class is adapting to what you're fighting and dropping appropriate totem combos. Another difficulty with mastering your shaman is the ridiculous amount of keybindings you could essentially end up with, if you are dropping single totems. This is why they gave us the 3 Call of the Elements buttons, to reduce the amount of button pressing in battle.
The amount of mana required to drop most 4-totem combos is almost negligible, and I don't remember ever having a mana problem dropping sequences of 4 in short order, except the rare occassion in a long BG fight or lengthy arena match where I'm down to a couple thousand MP.
That all said, I typically run two totem combos in arena and BG:
1st: earthbind, searing, mana stream, wrath of air
2nd: stoneclaw, searing, mana stream, wrath of air
Yes, they are the same except for the earth totem. The reason for this is simple: when you are in a pvp situation, you're rarely standing still. I need my totems to move with me, because I am most likely covering a lot of ground while kiting or chasing a druid.
Stoneclaw is an essential utility. Glyphed, and on a 20 second CD, you should be dropping it every time its available. Something many people don't know is that the shield you get from Stoneclaw persists even after the totem is recalled or replaced, so basically drop stoneclaw(group2), gain shield, drop earthbind(group1), repeat every 20 seconds. Your totems will "travel" with you, and you'll always be snaring enemies with a shield on you. It works well for me.
Have magma bound to its own key for when you want to flush out a stealther, also have grounding bound to its own key (or on the 3rd call of elements with other totems of your choice), to counter an obvious incoming spell.
I use searing over flametongue for extra dps because I play an aggressive healing/nuker in arena with my rogue partner. We have had relatively positive results so far.
When we eventually get 1 out of the 2 enemies down, or if we are having trouble with a strong healer, in 2v2, I'll drop Str of Earth and Windfury to buff my rogue.
Also, if there' a particularly strong mage, I might use Elemental Resistance totem to lessen the damage.
I hope this is helpful, but like I said, playing resto in pvp is 90% adapting to the situation at hand.