What would it be?
Take all pay and associated benefits out of the equation. Ignore prestige, job opportunities after the military, or what your family would think. If you could be any rank, which one would you choose?
Would it be:
A specialist, enough time in service to avoid the bad details, but low enough in rank to avoid having to take much responsibility?
A Captain, with his own company?
A Lieutenant General, with enough power to make real changes?
A First Sergeant, the top enlisted guy in a company?
A buck Sergeant, in charge of a group of enlisted soldiers, making things happen?
A Chief Warrant Officer, "the best rank in the army."