The current standard treatment for non-Hodgkin's lymphoma involves drugs called cyclophosphamide, doxorubicin, vincristine, prednisone and rituxan in a regimen called "R-CHOP." Using R-CHOP therapy, complete disappearance of disease is expected in over 50% of people. One of the active drugs in the R-CHOP regimen, doxorubicin, has previously been reformulated and been placed in a fatty bubble called a liposome. The reason for placing the drug in the liposome is that there is evidence that the liposome is better taken up by tumors. This liposomally encapsulated form of doxorubicin called Doxil has shown similar or better anti-tumor against certain tumors with reduced side effects. Doxil is FDA approved for ovarian cancer. However its use in non-Hodgkin's lymphoma is still investigational. By substituting Doxil for doxorubicin in the R-CHOP regimen, it is hoped this treatment will be better at shrinking tumors and with reduced side effects. The purpose of this study is to see how well the combination of Doxil, rituximab, cyclophosphamide, vincristine and prednisone (DR-COP) are in shrinking tumors in patients with non-Hodgkin's lymphoma.