I think its only bcoz of the locket horcrux that he left them in DH.

yes, it had a big incidence on his behaviour

It would depend on the situation. Ron loves both of them unconditionally.

~~ Hermione!! ~~
He really loves Harry too..

he had choose hermione,he always had a Crush on her,maybe since the first year of Hogwarts,but i think he really was in love with her from the 4 year!

its the situation like but like when harry had a go at hermione at grimmulaud place after lupin left and ron quickly said dont you talk to her like that and got in his face shows that he would take no nonsense from harry concerning hermione....i dunno if that made sense but lol

both Ron & Harry would choose eachother over everyone!

Hermione obviously. He does not always agree to what Harry says but agrees to what hermione says practically all the time. :)

Thats such a difficult question because I have always believed that Ron and Harry (probably being the guys) always had a stronger connection/friendship that Hermione and Harry as they have been through so much together.
And considering things like when Ron got Harry out from the Dursleys in CoS I'd like to think that he would consider choosing Harry.

But surely he should/would pick Hermione. Since the first movie you can tell that they have had a "thing" for each other, it just hasent been shown till DH, but honestly...I'd be really disapointed if he really did pick Harry over her. They're perfect.