The answer depends on why you are flying.
If you want to play, or pretend to be a WW2 Spitfire pilot, use a map and a compass.
If you want to go from A to B and be sure you won't bust some controlled airspace, etc, etc, etc, etc, get the best and biggest GPS you can afford. It will transform the accuracy and confidence of your flying. I have not done dead reckoning (or used the stupid circular slide rule) since the day after my PPL (except on various checkrides where I had to) and don't ever intend to. I have three GPSs in the cockpit, all with independent antennae.