This is an open-label feasibility study of fixed-sequence addition of lipid-altering medications, in which comparisons are made to the baseline for each subject. Subjects begin a lead-in phase in which they start the study statin (atorvastatin) or switch from previous statin therapy to the study statin. Subjects will wash off other excluded lipid-altering drugs during the lead-in. Subjects return for the first inpatient visit, where they have baseline studies on statin monotherapy. At the end of this visit, subjects are started on fibrate therapy (ABT335). They repeat the studies on dual therapy with statin and fibrate, and then add niacin (ER niacin). To minimize flushing during chronic treatment, they start aspirin 325 mg daily, or titrate to 325 mg if they are taking a lower dose of aspirin (e.g. 81 mg). Finally, they repeat the studies on triple therapy with statin, fibrate, and niacin/aspirin.