To the topic of original sin: I think the Word is pretty clear ( see verses below). We are born dead in sin because of Adams sin. When we receive Christ, we receive the incorruptible seed, and our spirit comes alive. (1Pe 1:23 Being born again, not of corruptible seed, but of incorruptible, by the word of God, which liveth and abideth for ever.) We can then commune with God. He can begin to convict us of our sins and transform our lives, if we allow and if we listen. Some receive the incorruptible seed, but it lands on poor soil and never germinates (read the parable of the sower). As we allow God to work in us, our new man (our spirit which contains the incorruptible seed), grows and get's bigger than the old man (Adam - our flesh and our soul). We either eat from the Tree of Life which feeds our spirit, our we continue to eat from the tree of the knowledge of good and evil, which leads to death. So, I guess my answer would be yes, we do still have our Adam nature, but we should be crucifying him daily, in order that our new nature may thrive, and have an impact on this world.
(Rom 5:12) Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned:
(Rom 5:14) Nevertheless death reigned from Adam to Moses, even over them that had not sinned after the similitude of Adam's transgression, who is the figure of him that was to come.
(Rom 5:15) But not as the offence, so also is the free gift. For if through the offence of one many be dead, much more the grace of God, and the gift by grace, which is by one man, Jesus Christ, hath abounded unto many.
(Rom 5:16) And not as it was by one that sinned, so is the gift: for the judgment was by one to condemnation, but the free gift is of many offences unto justification.
(Rom 5:17) For if by one man's offence death reigned by one; much more they which receive abundance of grace and of the gift of righteousness shall reign in life by one, Jesus Christ.)
(Rom 5:18) Therefore as by the offence of one judgment came upon all men to condemnation; even so by the righteousness of one the free gift came upon all men unto justification of life.
(Rom 5:19) For as by one man's disobedience many were made sinners, so by the obedience of one shall many be made righteous.
(Rom 5:21) That as sin hath reigned unto death, even so might grace reign through righteousness unto eternal life by Jesus Christ our Lord.