People can be inspirational without being perfect. Despite his failings later in life, Shackleton acted honorably and courageously on the Endurance mission.
On one of his expeditions, after their ship got stuck in the ice, Shackleton basically saved the lives of every single man on the mission through excellent decision making. I have read accounts of several 'Heroic' exploration missions, and in too many of them, the leader sacrifices the lives of his team mates to "win". Shackleton seems to have been the exact opposite of that.
"Shackleton's concern for his men was such that he gave his mittens to photographer Frank Hurley, who had lost his during the boat journey. Shackleton suffered frostbitten fingers as a result."
"Shackleton immediately...set to work to organise the rescue of the Elephant Island men. His first three attempts were foiled by sea ice, which blocked the approaches to the island. He appealed to the Chilean government, which offered the use of Yelcho, a small seagoing tug from its navy. Yelcho reached Elephant Island on 30 August, at which point the men had been isolated there for four and a half months, and Shackleton quickly evacuated all 22 men."
http://en.wikipedia.org/wiki/Ernest_Shackleton#Loss_of_Endur...