I think you're right. I found that all my materials had the color layer (of their associated PSD file) connected to both their color input and their transparency input. When I fixed this, it stopped crashing. The really strange thing is I couldn't figure out how that happened, so I ran a little test.
I opened a new file, created an object, assigned a new material (blinn) and created a PSD file for that material (with only color, bump and spec layers-no transparency). When I graphed the network everything looked o.k. Then, I minimized Maya to put a texture in the color layer (In Photoshop). When I brought Maya back up (and before I even had it reload the PSD file) the color layer was connected to both the color and the transparency inputs of the blinn!!!!???? WTF? Anyone have any clue what this might be? or is my version of Maya just haunted? And thanks NextDesign for the help.