Personally I still recommend the config file. Even when they are simple, it gives you one single source of truth that you can refer to, it will grow as you need it, and it can be stored in source control.
Where and how parameters are configured is a bit more of a wild card and dependent on the environment you are running in.
That's something Matt and I tend to disagree on - I agree that a config file is better almost always because it gives you a better starting point to experiment with other features.
Where and how parameters are configured is a bit more of a wild card and dependent on the environment you are running in.