Hmmm...not really sure. But I think that God manifests himself to each of us differently...in whatever way is necessary.
For example, the story of Jacob wrestling the man/angel/God (Genesis 32). Jacob first sees only a man and they wrestle through the night, neither refusing to submit to the other. In the book of Hosea, the 'man' whom Jacob wrestled is referred to as an angel. Later in the same chapter of Genesis, Jacob asks the name of the 'man'. The 'man' refuses to give his name but Jacob replies that he had "seen the face of God." Jacob wrestled with God in the form of a man. [The purpose of this wrestling match was merely to show Jacob that he must stop relying upon himself and give himself fully and completely to God, and there he would find his strength]
John 1:18 says that no man can look upon God (in his spiritual form) at any time...at least while we exist here on Earth. But God made himself visible to many Biblical people. The Bible says that God walked with Adam in Eden...that God led Lot out of Sodom by the hand. Jesus said that when you look upon Him, you look upon God.
Okay, rambling, sorry. I guess that I believe that God can manifest himself into whatever physical form is necessary. As far as a spiritual form, I have no idea. A warm, bright light, filled with every color imaginable? Something like that anyway.
Remember that movie, Michael...John Travolta as the angel, you know? Well, remember how all the women loved to be near him because of the way he smelled...like Grandma's sugar cookies to one, like warm apple pie to another? I think God will be something like that to each of us. The best smell, the most beautiful face, etc that each of us could ever imagine.
Love, Heather
faceless giant sitting on a throne. When I was small, that is how I pictured God. I don't have a visual image of God anymore but Triton is a funny image. I can hear him saying "Arrriiieeellll!" 
