I just came through pre-clearance and security at YYZ headed back to SEA through ORD.
I packed all my stuff: laptop, ipod, bose headphones, chargers, cables, overnite change of clothes (just here for one night), liquids (in baggie), other toiletries, book and newspaper into my computer bag. I went through security with no questions asked.
I went through a secondary screening on the way to the gate. They pretty much took everything out of my bag and looked through every pocket. No issues with my computer bag or it's contents. The patdown I received was about as extensive as I have ever received.
Looking around the boarding area, if you have a reasonably sized computer bag, and it has a computer in it, you can also put your other carryon items into it without any problem. One of the security gals told me that they are not allowing any computer bags with wheels.