I am a paladin tank... I have 10% spell damage reduction between improved righteous defense and spell warding, and a 3% increased chance to completely avoid spells from pursuit of justice. On top of that, we are the tanks that can on the fly increase our resistance to fire, shadow, or frost magic by simply changing our aura. With a holy paladin in my party, and a shadow priest in my raid, I have very good spell damage mitigation against the three forms of magic that get thrown at me by the spell shades in Kara for example (which allows them all to be tanked with no CC).

Murmur is kind of a pain, but if you have enough hp, you can just eat a sonic boom. If your DPS is where it should be he won't even be able to get a second boom off, so you could just bubble through the first boom.

The big multi-mob pulls in SL are cake if you just mark the targets to die in the proper order. Kill the acolytes (healers), then the shadow priests (most of the damage), and the rest is cake. Most of the spell damage can be mitigated with shadow resist aura. As a paladin tank I always mark casters to die first, because physical damage dealers are a joke as they kill themselves on my holy shield.