For posterity? Quintana. By like, a really long way. The Olympics are still at a rate of kind of figuring out what their prestige level is within pro cycling, since they've only been contested by the pros since the 90s and some people rate them very highly because of the rarity and others rate them comparatively lowly because of not having the same historical prestige or value as the Worlds or the Monuments.
GTs tend to be remembered more in posterity because they're harder to win as a fluke, whereas a one-day race can always be misjudged or something strange happen on the day like Oliver Zaugg being the strongest man on the day or Jacky Durand not being caught.
Also Kristoff and Degenkolb seldom came into major classics as 'the red hot favourite' despite their achievements because they were largely seen as sprint threats, which has them behind GVA for me. Obviously both were seen as more than sprinters, but sprint wins and challenges tend to be more fleeting and less valued long term than winning on guts and tactics, we don't tend to go back and rewatch sprint stages unless something unusual happens, so I think that a lot of their wins will be less well received by posterity than the others, and GVA will be valued more in the distant future because he got his placements in more memorable and fashionable ways. The way Kristoff won his Ronde elevates him above Degenkolb for me (especially as 2015 Roubaix was a much-disliked edition), but the way Quintana came in as a major player and, if not the absolute favourite, then the expected main opposition, for the best part of a decade has him at a higher level. He has more 'signature rides' as well as having won two GTs and podiumed multiple others (and crashed out of another while leading).
Purito is the hardest of all of them to rate. He has that whole GT side to him that the others who primarily won one-day races don't, but simultaneously he never actually won one, and is most famous for capitulating in the time trials, losing GTs to the likes of Nibali might be acceptable to posterity but Ryder Hesjedal in the most conservative GT ever raced? Ain't nobody clamouring to re-visit that race, and it would be hypocritical of me not to count that against him in the same manner as 2015 Roubaix being poorly-received meaning it won't be one people go back to being held against Degenkolb's legacy. Similarly, Purito has a very good one-day palmarès especially in the hilly classics with the likes of Flèche as well, but his one-day ride that will perhaps be most remembered will be the 2013 Worlds in Firenze where Valverde falling asleep at the wheel cost Spain the gold and left Purito completely helpless at the end.
However, one thing in Rodríguez' favour is the whole concept of the murito being pseudo-named for him, following his nickname and the likes of the Muro di Montelupone becoming pure Joaquím Rodríguez playgrounds.