My rule of thumb when deciding to plan to ride is a wait time of less than 30 minutes. This means that if I want to ride TT, FoP, 7DMT, etc., I need to get a fast pass. The trade off of not waiting in line is missing out on all the cool things that they added to entertain you while you are waiting in line.
How long are you willing to wait in a line?
Are there any rides that are an exception and why?