The important thing is that with regard to position, the GPS does not tell you anything you don't know already.......especially when using the moving map.....the only diference is that the position where the GPS thinks it is can be a little clearer becuase very few towns in Europe have their name laid out beside them.
Also even if the GPS tells you where you are know, you still have to navigate from there to where you want to go.
So by all means get a GPS but I would not let the GPS become the Captain of my aircraft!!!
As for local area navigation........that is usually the hardest of all because you are operating in a relatively confined area and are trying to navigate as accurately as possible often ad-hoc and with little time available for correction.....................Remember three rules;
1. Aviate, Navigate, Communicate
2. Keep ahead of the aircraft even if this means stopping progress for a while to get things together -orbit, hold, whatever.
3. Use the big picture. I once declared to my instructor that I was lost......he simply turned round and said that I could not be lost as I had not left the country so I should start there and work down from that.......today, I see many pilots fretting over what the village passing under the nose is when 1 O'Clock at 3nm is a massive town with two motorways!!
Until you are familiar with your local area....work out some "standard Arrival/Departure routes" that will help you get to and from the airfield. Also measure how far a certain feature on that route is from the airfield and use that feature to trigger the joining call because you already know the distance and direction.
Finally,
The most likely way of getting lost is not paying enough attention to heading and time.
For say a C150, the most you will ever drift is 2/3 or so of the windspeed at height in degrees. So if you make absolutely no correction for a 30Kt wind, you will drift by a maximum of 20degrees. That is 20nm off track in 60nm..........but it is only 5nm off in 15nm...............so provided that you check your position every 10 minutes, you will never be more that 5nm off track unless there is a crosswind of more than 30Kt....................5nm isn't that far off.....and that's after 10 minutes.............if you make no correction for wind but check your position every 5 minutes, you will never be more than 2.5nm off track............Now do you really need a GPS?
Having said all that, a GPS can be a great tool for backing up ETAs and suchlike for ATS especially when they ask for an ETA miles down the road.
Regards,
DFC