RATIONALE: Giving chemotherapy before a donor peripheral stem cell transplant or bone marrow transplant using stem cells from a brother or sister that closely match the patient's stem cells, helps stop the growth of cancer or abnormal cells. It also helps stop the patient's immune system from rejecting the donor's stem cells. The donated stem cells may replace the patient's immune cells and help destroy any remaining cancer or abnormal cells (graft-versus-tumor effect). Sometimes the transplanted cells from a donor can also make an immune response against the body's normal cells. Giving colony-stimulating factors, such as G-CSF, to the donor helps the stem cells move from the bone marrow to the blood so they can be collected and stored. Giving methotrexate and cyclosporine before and after transplant may stop this from happening. It is not yet known whether a donor peripheral stem cell transplant is more effective than a donor bone marrow transplant in treating hematologic cancers or other diseases.