On the Steel Breeze is the second novel in the Poseidon's Children trilogy (series?) by Alastair Reynolds. The Akinya family's still in the protagonist role but the series didn't turn out to be the kind of family saga I was expecting -- hoping, even. I don't know how the Akinyas managed to squander their riches but they did have the time: this novel takes place a couple of centuries later. Only a single human generation has passed, though: aging having been defeated once again.
