I don't believe that being "born again"/"saved" has anything to do with the denomination or church that you attend. Although, there are certainly denominations/churches/religions that do not teach the truth of the Bible regarding being born again. People who attend those churches have to find the truth through Bible reading or other people outside of their church. There are other churches that teach the truth of the Bible from the pulpit. Some churches/people twist scripture to make it work for them.
To me, being born again or saved is when you ask the Lord/God into your heart, ask his forgiveness of your sins and profess that Jesus is your Lord and Savior. You then begin a daily walk with Him and living according to His word. You become His child.
It frustrates me that the term 'Christian' is used so loosely in our society. People call themselves 'Christian' all the time but do not live a Believer lifestyle according to God's word. I like the term Believer, as was used in the Bible, as most people who use that truly are living the life as God intended and wanted for us. That means voting for scriptural values and upholding those values in our everyday lives.
Do we fail or sin? Yup, we are all human - the only perfect human was Jesus. We need to ask for forgiveness from our Heavenly Father when we sin (what is sin? That's another topic... I believe that sin is a willful transgression against the KNOWN law of God). How do we know God's laws? By reading His word and having regular devotions and prayer time with Him. Yah, I know... there is tons of theological debate here I'm just trying to keep it real simple.
I like the NIV but keep the KJV close and use other sources to help me understand the verses I'm reading. Strongs Concordance is a great help. I totally agree that people should read and study which ever version speaks to them and brings them closer to God. But, you do want to make sure that it's as close to the original version (Hebrew for the Old Testament and Greek/Aramaic for the New Testiment) as possible. There are "Bibles" out there that have pretty much nothing written in them that was God inspired.