Edit: I got off my lazy bum and made a new Totem Guide. The Cataclysm Totem Guide: Part 1 can be found by clicking the link provided.
When people think of Shamans, they think of two things: Heroism/Bloodlust, and Totems. More often than not I see Shamans making use of their totems in an improper way. Here's a basic guide to totem usage.
Strength of Earth Totem
Wrath of Air
Mana Spring (Unless there's a Paladin giving Improved Wisdom)
Wrath of Air
Okay, here's the skinny.
The water totems (Healing/Mana Spring) are situational totems. If there's no Paladin giving out Wisdom or a Resto to toss out Improved Mana Spring totem, an Enhancement or Elemental Shaman may toss out Mana Spring to help maintain the mana regen of casters; if there’s already a source of mana return (via another Mana Spring or a Paladin casting Wisdom) then toss out Healing Spring.
Fire totems are a bit more spec specific. For Enhancement, if you're specced into Elemental Fury, an aggressive totem such as Searing or the Fire Elemental is the most beneficial totem for our DPS, even with Flametounge being improved for us. Magma Totem paired with Fire Nova will still probably be the AoE combo of choice, but Magma should no longer be used on single target bosses.
Earth totems. There are mainly two that are used: Strength of Earth and Stoneskin. Unless you are specced as Enhancement, or there are NO Death Knights in your group, do NOT use Strength of Earth. More often than not I come across a Resto Shaman who tosses down SoE with a DK in the group, and it's a complete waste of a potential buff and mana. It doesn't stack at all with a DK's Horn of Winter. The typical best option for Restos or even Elementals is the Stoneskin totem. This totem increases the armor of the party and/or raid. In the event that there's a fear (and you know about it, as you should if you look up mechanics ahead of time),you’re your Tremor totem...keep in mind that this totem is party only. Earthbind totem also has some nice situational uses.
Air totems! As a rule of thumb, typically use the one that benefits you personally. Meaning, if you’re Resto or Elemental, generally toss out Wrath of Air. If you're Enhancement, Windfury totem is your air totem of choice. Now, sometimes it's more beneficial to use one that may not directly benefit you, but helps out the group as a whole. Say, there's an Elemental Shaman and a Restoration Shaman in the group. Obviously if they both put out Wrath of Air, one of the totems is potentially not being used (though a larger radius can be nice in some fights), so one of them may opt to put out Windfury totem for the melee folks.
It's okay to double up on some totems so long as the other available buffs are covered...as I said, the increased radius is sometimes quite handy, depending on the fight and how big the area is. Just be mindful of the buffs present, and adjust your totems accordingly.