To evaluate, in HIV-infected patients whose baseline CD4 count is 300 to 750 cells/mm3, whether an antiretroviral treatment regimen based upon clinical evaluation and CD4 counts plus HIV RNA viral load is more effective than a treatment regimen based upon clinical evaluation and CD4 counts without the use of HIV RNA viral load information. To assess relative utility of viral load testing in determining therapeutic choice by the surrogate marker of CD4 cell counts after 48 weeks of therapy.