When we first came to Northern Ireland we made a road trip all around the coast it was great we had a vw van that we could sleep in and absolutely everything was magickal - In those days 25 years ago there was little difference monetarily between North and South but then the Celtic Tiger arose and it got pretty expensive and we got too old for sleeping in the van.
My favorite so far (and I've had several) was landing in Anchorage, renting a car, and driving all around Alaska (not the outer areas that had to be reached by sea plane/boat): Fairbanks, Telkeetna, Homer, Seward, North Pole, Denali, and a few other places I'm sure I'm missing. It was amazing!
Wow, I used to take lots of road trips. Before I was married and had kids I'd take off on a whim. I had a CB radio, used to talk to truckers. I took a few with the kids, they'd get nervous when I went off on boondoggles. I need a road trip soon.
I spent eight years walking the world. Started in San Diego and went South. Returned through Canada back to San Diego. West Africa and the Mediterranean islands of Corsica and Malta were awesome. France and Germany were o.k. I would do it all again and again.
Best or most memorable? My former partner, I and her 2 parents went (in my Honda Civic Hatchback) from Heidelberg to Amsterdam. We then took an overnight ferry to Hull, England and to Edinburgh Scotland. From there we drove to Inverness (to see Nessie she stood us up) and then on to the infamous "Path of the Cattle". I heard OMG from the mother in the back seat more times than I cared. Either cars going in the opposite direction or herds of sheep in the road. It was a nightmare. If you watch closely you will see small openings on the right. That is for one to pull over in case of an oncoming vehicle. One has to be wide awake! After Applecross we took the coast road back which was only marginally better. Scotland is the pits to drive in. Pay attention to the end.