Ahhh. Then that's entirely subjective!
205 GTi - group B rally car and saved peugeot from closure
Lancia - first 4wd rally car or something?
Clio 172 - erm, cheap and cheerful track car that floods every track day
Think it needs some story/purpose to be a proper icon/classic
205 GTi was not the homologation version of the group B rally car, that was the 205 T16, immediately recognisable as the engine is in the back, much the same as the R5 Turbo (not to be mistaken for the GTT). The 205 GTi is essentially very similar in idea and history to the MK1 Golf GTI and the Clio 172 IMO, in that it was cheap, quick, but not a homologation car, nor made in limited numbers, just made to be fun. Look at the rate people break 172's now days, the numbers must be dropping off, as young drivers can't insure them, and who else wants to run around in a 14 year old french hatchback? I think the clio's will get there but not in the near future.
The Lancia, I assume you mean the Lancia Delta Integrale, wasn't the first 4WD rally car, the first successful top flight 4WD rally car was the Audi Quattro. However the Lancia was the homologation version of a group B car, and that's why the Integrale Evo 2 prices are edging ever closer to 100k. Silly money really, but everyone loves to pretend they're Ari Vatanen.
I think the clios will follow in the footsteps of MK1 Golf GTI's and 205 GTI's, especially the Cups and Trophies, but the Lancia is in a different league in terms of how collectable they will become.