Recommendation to Shooting Long Videos I'm seeking recommendations on how to shoot a long lecture by a guest speaker that is coming to town. I currently own a Canon t4i. My main question is what do I need to avoid my camera from spazzing out during the lecture. What SD card might I need? Will the battery run out? How to avoid that?

Thanks
The biggest trick you will run in to is the 4GB file size limit and the 30 minute record time limit.  You will need to monitor the recording and resume several times or use a third party software like Magic Lantern to overcome the limitations.  As for battery, there is a DC adapter available that you can buy if battery life is a concern.