I waited outside on the sidewalk for a Nintendo Wii on launch day two years ago...I've also done the Black Friday thing several times. I can tell you that if you don't mind waiting, Black Friday shopping can be a lot of fun. Make sure to go with a friend or two and make a day of it; plan to go out for lunch, etc.
Just go with the mindset that traffic will be horrific, you will be waiting in line a LOT, some people will be rude and crazy, and you might not get everything you wanted to end up with. Usually, I go on Black Friday without any specific goals for what to get. I play it casual and just see what is available. It ends up being an adventure, and I usually find some really good deals (plus, the people watching is spectacular!).
Make sure to wear comfortable clothes and walking shoes. High-heeled boots are a definite NO. Wear a warm shirt so you can leave that heavy coat in the car. Bring entertainment like a cell phone with the Internet, iPod, Nintendo DS, etc. so that standing in line is more entertaining.
If you are a type-A person who has a short temper, just stay home and shop online.
Black Friday is amusing, but it's not for the impatient or easily annoyed.