Why did DD take Harry with him?

[pippin_999]

DD explains why, despite his skepticism about the prophecy,
he believes Harry has to face Voldemort. But I was wondering,
why did he think it had to be Harry to find the horcruxes?
It seems to be a task that requires a great deal more magical
knowledge than Harry, or even Hermione has. 

So why did he bring Harry with him to fetch the locket?
As plenty of people have pointed out, a House Elf could supply
an extra pair of hands. Further, I've realized Jo gives us a broad
hint that extra hands weren't really necessary. As we saw at
the Dursleys, Dumbledore can enchant a cup so that it will  try,
with increasing insistence, to force you to drink it. We also saw 
Harry use a refilling charm.

DD could have gone to get the horcrux and then had Harry
relive the experience with him in the pensieve -- much safer
for Harry, right?

Then it dawned on me that out of our pitifully small sample set,
Harry is the only one who has destroyed a horklump without 
harm to himself. Considering the whopper of a curse that was
on the ring horcrux, that's probably highly significant.

And then I remembered the strange affinity
between Harry and the Diary. 
---
The fact was, even though he *knew* the Diary was blank,
he kept absent-mindedly picking it up and turning the pages,
as though it were a story he wanted to finish. And while Harry
was sure he had never heard the name T.M. Riddle before,
it still seemed to mean something to him, almost as though
Riddle was a friend he'd had when he was very small, and
had half-forgotten. -CoS-US 233-234 (ch 13)
--

Also, Harry knew how to destroy the Diary, a powerful
magical object, without being told.
--
Then, without thinking, without considering, as though he
had meant to do it all along, Harry seized the basilisk
fang next to him and plunged it straight into the heart
of the book. -- CoS-US 322 (ch 17)
--

I think that Dumbledore hoped there was some connnection
between Harry and all the horcruxes that would enable him
to recognize them and destroy them, perhaps even sense
how to bypass the protections surrounding them.  Of course 
DD was unable to test this theory, except in a negative way,
 because the locket horcrux was a fake. 

But this would explain why DD might think that Harry could
continue the task of hunting horcruxes without him, though
Harry knows none of the magic that enabled DD to reach
the one he found. Provided, that is, that  Snape was alive to 
save Harry from the effects of whatever Dark Magic was used to 
protect them. That would provide a motive for Dumbledore to 
sacrifice himself to save Snape.

I'm wondering if Dumbledore didn't leave in Snape's custody
a parting gift from dear old Nicholas? And whether we won't
get the true proof of Snape's loyalties when he and Harry are
both at the verge of death and Snape uses the last dose
of elixir of life to save Harry. Snape doubters, would that 
convince you?

I'm also reminded that Dumbledore thinks he would have died
if Snape hadn't saved him from the curse. If what we have
is WYSIWYG!Snape, why didn't Snape just let him die?

Pippin