Oz,
I would not discount the miraculous today. I did not intend to say that miracles cannot happen nor that a Christian could not have a miraculous gift. I was simply trying to underline the notion that we are not to be sign-seekers or be people who strive to validate their beliefs with miraculous proofs. I simply do not think such works are to be considered normative in the Christian life. There is nothing in all of Christian history that would suggest that miracle working powers were commonplace among everyday believers. I think the NT calls them "signs" and "wonders" for a reason. As Stan pointed out, the NT indicates that not all would have such gifts, and, unfortunately I feel that those segments of Christianity that argue as much often fall into emotionalism and have an unhealthy fascination with signs and wonders. In fact, when Paul speaks of Christian maturity, he uses the fruit of the Spirit as his barometer, not the ability to perform miracles. It seems there were Corinthian believers with such abilities who were also very carnal and ungodly in their behaviors.
As far as the quote from Jesus, I do think Christians have done greater works. I think this is testified to in the book of Acts. More importantly, I think these works Jesus speaks of reflects primarily on the preaching of the Gospel. Jesus empowered his followers to preach a message of eternal life to their hearers. Jesus never preached of faith in his death, burial and resurrection. Jesus never proclaimed a message that brought the gift of the Holy Spirit into the life of his hearers that He might dwell in them and empower them to live a sanctified life. I think this is the focus of what Jesus is talking about. Remember what Jesus said to the seventy when they returned from doing miracles and preaching the Good news of the Kingdom,
Those who preach the Gospel have recieved power from God to share a message that can free a person from sin, enscribe their names in heaven and grant them the Holy Spirit of God to dwell in them and testify that they are children of the Almighty God. Paul's primary focus as a believer, even to his dying day, was not the power that was at work in him to heal the sick and raise the dead, but the advance of the Gospel.
One day we will stand in that heavenly, eternal kingdom. Then we will realize the power of God. That power is most fully on display, not at the raising or healing of a mortal body that is destined to perish, but in transforming of a person's eternity by preaching the blood of Jesus that cleanses and saves the sinner's soul.