Right party could have been his own. Well even if we suppose Congress then how nice would that have been. No SG thrust on the nation.
BJP is his own party Yusuf bhai. Vajpayee played no lesser role than SP Mukherjee or D Upadhyayay. It was for him the party gained the mass base it has now.
The Vikash Purush of BJP is arguably the biggest figure in Indian politics after Neheru. It is no secret that people remember his rule fondly and still wish to see him back as the leader of the nation. Sigh, if it only were possible.
However, the point remains, he was the right man in the right party. Furthermore, if you understand the basic tenets of Hindutva and closely relate with Atalji's life and work, you'll invariably infer that BJP and Vajpayee were meant for each other.
My salutations for this great man.