Which Witches Will You be Denying?

[The Tisroc]

Friends,
Now that we have a Psychic Phase (which seems to borrow heavily from WFB's Magic Phase) we are going to have to pay attention to one more bit of resources management: we're going to have to shepherd our dispel dice, spending them when they matter the most.

In WFB there are a few big spells that players hold dice back for: Purple Sun and Throne of Vines spring to mind. What are the biggies that you'll be holding dice back for in 40K? What witchery absolutely must not see the light of day, in your opinion? Which witches will you be denying?

I'll start: I'll probably be sitting on as many dice as possible to dispel Prescience. I hate that damn power. Cheers.

[This Dave]

Invisibility seems to be a power that needs to be killed with fire if attempted.

[jifel]

It does seem like it'll be common to hold back dice for one big deny attempt.

[Demonus]

Sadly none, cause I play necrons, and we lost pariahs