I personally consider All Star Superman a more proper ending...
Well, the problem with All-Star Superman as an end to the Bronze/Silver Age Superman is that they're pretty clearly not the same guy. Silver Age Luthor, for example, is a much more respectable, noble man than in All-Star (I ultimately prefer heroic Luthor, though it has little impact on my enjoyment of All-Star). In All-Star, there's no Supergirl in Superman's time, though she makes an appearance as Superlass of the Superman Squad (and apparently a member of the Legion). Most importantly, there's no Leo Quintum in the Silver and Bronze Age. This brings my to my next observation.
Lex Luthor saw the errors of his way and right before his execution redeems himself by giving Superman's DNA to Leo Quintum, which should lead to what would become the Superman Squad in the future. This shows that despite everything, Superman was right all along about Lex having potential for doing something great.
Now, this is interesting, because though few people notice, this is alluded to in the comic as well. I'm afraid I'll do the idea little justice, especially compared to some of the blogs that talk about it, but it's pretty heavily implied that Leo Quintum
is Lex Luthor in disguise, come back from the future after his change of heart following his aquisition and loss of Super-Powers. Quintum claims to be running from the past, though we never see exactly what that is. He's unsure of whether he deserves Superman's trust. He purposely goes on his mission to the sun in order to ensure Superman gets the power boost necessary to save the sun from Solaris. He and Luthor also share a numerical motif: the number five. The issue that deals with Luthor in prison is number five. Leo
Quintum also has a lot of the number five permeating his story, though sadly, I forget where exactly, besides the name. Why does the mainstream DCU have no Leo Quintum? Because Luthor hasn't had his change of heart and become him in the mainstream DCU.
Finally, I've got one more thing to say:
Anyway, after some thought, I've finally found my candidate for Worst Version of Superman Ever:

I
KNEW I was forgetting someone! The real crime of this guy is that he should be really cool. Just listen:
Superman, in the future, fighting twin metahuman clones of Adolf Hitler, who are in charge of an army of robots and monsters. That sounds great to me, and it's still awful. The worst thing about this guy is that it's a good idea, and it's still bad, much like the "Speeding Bullets" Elseworld where Kal-El becomes Bruce Wayne instead of Clark Kent. Should be a good idea, but the execution ruins what I had in mind when I picked the book up.