In the UK mine has to be the SW Coast Path. I have that in mind for when I retire (a long way off yet) as I would just love to go off for a couple of months and lose myself in the experience.
Further afield, I would like to do the Pyrenean Coast to Coast, i.e. from the Atlantic to the Med.
But I also have in the back of my mind, the West Highland Way, the C to C, the Penine Way ...
I've also done some planning of my own, for a shortish unofficial LDP. Having walked the 2 Moors Way, I noted that the path crosses the Eastern side of Dartmoor. While I have no problem with that and understand the reasoning (the west side is where the ranges are, which restricts when they can be walked), I would like to do a South to North traverse across West Dartmoor. This really is wild country, with few footpaths and where good navigation is essential. The terrain is very difficult in parts, so I've been thinking in terms of a 3 day walk to get from Ivybridge to (perhaps) Okehampton, with probably no option but to wild camp.
S.