I've also found that magma/searing are good choices for encounters where you have to move or heal a lot. They give you some constant DPS which added with shocks can tip the scales for you. Talon King Ikiss and Hungarfen are examples of fights where searing or magma totems can make the encounter a lot easier. The Ikiss encounter gets two benefits from searing/magma. First, I had to heal a lot on this fight and that cut into my DPS. The searing and or magma totem kept up some DPS when I was healing. Second, after Ikiss does his AE, he would run to a shaman who had just healed, but with searing down, he would run there giving me a few seconds to heal and pick him up with the paladin.

On a side note, as Vyndree stated, ToW makes a huge difference on mana consumption. I just respec'd for PVP on Sunday dropping ToW for NS and I ran Mechanaar and SL last night. I used considerably more mana than I did last week when I had ToW. There were lots of fights I would end at 80% or more mana with ToW where now I end with 20-40%. This means that I have to drink a lot more frequently. With ToW, I would rarely have to drink between pulls as water shield usually regenned all the used mana for a fight.