I'm curious as to how many people actually do this.
I'll be upfront with you in saying I think this is just stupid and it frightens me that people who are in IT security think this is a good idea. I wouldn't call myself an IT security expert, but I am fairly security conscious and I think that if you're putting tape over your camera, you're missing the point completely.
Turn on your webcam once and look at yourself as you use your computer. What do you see? Your face staring squinty-eyed at your laptop- oh noes, they might be able to see your facial expressions! Be less worried about that, than the fact that someone may have so completely owned your computer that they have to ability to turn on your camera and watch you remotely. Your real "dirt" isn't on your webcam- it's on the PC itself. If they get your bank account information from your PC, then you've got a real problem- and it's one that a piece of tape won't fix.
In short, if they can control your webcam, you've already had information about yourself exposed that's worse than anything they're likely to see. Be security aware, and keep hackers out of your PC to begin with.