Andrew Strom says the Gospel is conviction of sin, deep repentance, water baptism and getting filled with the Holy Spirit.
Joel Osteen seems to think it's positive thinking and admits that he was very influenced by the writings of positivist Norman Vincent Peale.
Rick Warren believes the gospel is....ummm....well..I'm not sure as it seems to be inconsistent to me. Sometimes he will preach the cross and other times a more positivist you-have-a-purpose message. Lately, it's been a help the poor message (especially in Africa, although there are poor here too, right?).
The Young Calvinists believe it consists of Jesus being punished in bearing our sins and a lot of talk about hell.
The emergent [villagers] think it is helping the poor and bringing peace and justice to the world much like the liberal Protestants think. Not much if any, cross preaching.
Others, like some Charismatics and Pentecostals, stress healing as the main part.
And others stress financial prosperity as the main part.
What do you think is the central part of the gospel - what we all should preach, that is, although there may be variations of course.