I find Black Friday to be pretty lackluster. The sales are almost never on the actual PC parts (ie; CPU, Mobo, GPU...). If you're looking for a mouse or keyboard, maybe a headset, there might be a sale. In the end though, if something you're looking for is on sale right now, just pull the trigger and buy it now.
Now if you're looking for a 40"+ 1080p TV, then hold off for Black Friday.