Mother Night and Father Time were the progenitors of the Endless, but they themselves were not part of the Endless.
And technically the most powerful of the Endless would be Dream, because he—with the help of a thousand dreamers—has the power to alter reality to a degree that puts even his siblings at his mercy.
From Sandman: Overture #1
For second place you could argue that it would be Death—since she's supposed to be the last one around—but she doesn't decide what time and place, so it's not as if she could reap them outright.
It's basically always been implied that their power corresponds to their age, so it would be:
Destiny
Death
Dream
Destruction
Desire/Despair
Delirium
The problem is Destiny is completely passive due to openly acknowledging that he is bound to predestination, so even though it's been implied he is more powerful than the others, it's hard to tell as he doesn't really do anything.
The rest of the order corresponds pretty well though, with Death definitely having more power than those younger than her (scaring the furies and most of the beings at the council of the first circle, many statements about her not having to follow rules, the fact at some point she sulked about her role and death stopped in the universe for millions of years etc).