Someone asked for a biblical perspective, and while I am no theologian, I will give it a shot.
The Bible is very clear on this subject. Jesus taught that He is the Way the Truth and the Life. He stated that no man comes to the Father except by Him.
Salvation is by the grace of God; it is given through Faith alone. No amount of good works, ceremony, or sacraments can gain you entrance into heaven. Simply FAITH in the the fact that Jesus died for the sins of ALL men. But one must ask for forgiveness for one's sins (repentance) and believe on the LORD and His plan of salvation (Jesus Christ--God Himself--- entering the earth through the space/time continium, dieing on the cross and then conquering death for ALL by rising from the grave and ascending into heaven). This plan of salvation is prophesized throughout the bible clearly. Jesus fullfilled all that was prophisized about the messiah.
According to the bible "absent from the body", present with the Lord". At which time we will all be judged. None can enter on his/ her own righteousness, but only through the righteousness of Christ who bore all of our sins.
According to the bible He intercedes with the Father for us, and we take on His righteousness. Since God cannot allow sin in His presence we must be made righteous in order to enter heaven.
The bible is also clear that the beauty of heaven cannot even be comprehended by the human mind, and that it truely is "paradise". One must choose to receive this free gift through an excercise of our free will however.
Sadly, many have too much pride to admit they have sinned and to ask Christ into their lives.