Not quite up for regular posting yet, but here is my take on why apologists using the "existence" immaterial concepts as rationalization for why an immaterial God is possible fails.
A popular thought in religious apologetics lately is that there are examples of things that are immaterial in which atheists can't deny and that these things make an immaterial deity possible.
Here's the problem:
The examples of these immaterial things aren't things, they are concepts. Yes, thoughts are immaterial--they are also fundamentally different from an active agent like God. Thoughts are completely dependent on a thinker, but to call the thinker an immaterial consciousness analogous to God is just as fallacious. The prerequisite for consciousness is a brain. To say that God requires no material prerequisite is special pleading and contrary to all evidence.
I floated this take on Google+ and it spawned 100+ comments. Here's the link.