I have to go with the gold group due to Yamaguchi and Arakawa, both of whom were incredibly talented overall skaters (and both of whom are among my top 5 female skaters of the past 25 years).
But it's extremely close, due to Kwan and Ito in the silver group. Kwan is arguably the best female skater overall in the past 25 years (based on results alone). And Ito's athletic accomplishments are legendary; she's probably the greatest female athlete in the history of the sport. Plus, this group also includes Cohen, who's among the greatest artists! Tough choice.
I've always felt that winning the Olympic silver is nearly as great as an accomplishment as winning the gold, mostly because it is often so very, very close between gold and silver. Torino was an exception to this; but many of the other Olympics have been virtual photo finishes, with results that continue to be debated to this day.