This study will compare the proportion of subjects who sustain suppression of plasma HIV RNA to undetectable levels among the three regimens during the maintenance phase; evaluate the proportion of subjects who exhibit no resumption of HIV replication after therapy is withdrawn; to evaluate CD4 and HIV RNA levels at baseline and CD4 cell counts at time of randomization to the maintenance phase as a predictor of successful maintenance therapy; to evaluate the drug resistance of breakthrough isolates; and to evaluate kinetics of HIV RNA and proviral DNA doubling in subjects in whom viral replication increases after withdrawal of therapy.