DISEASE CHARACTERISTICS: Pathologically confirmed acute myeloid leukemia Not in first complete remission with translocations t(8;21) unless failed first line induction therapy Not in first complete remission with translocations t(15;17) or 16q abnormality unless: Failed first line induction therapy OR Molecular evidence of disease Pathologically confirmed acute lymphoblastic lymphoma (ALL) Not in first complete remission OR High risk ALL in first complete remission defined as: Hypodiploidy OR Pseudodiploidy with translocations t(9,22), t(4;11), or t(8;14) OR Elevated WBC at presentation Greater than 100,000/mm3 if 6-12 months old Greater than 50,000/mm3 if 10-20 years old Greater than 20,000/mm3 if 21 or over OR Failed to achieve complete remission after 4 weeks of induction therapy Pathologically confirmed chronic myelogenous leukemia (CML) not in blast crisis Pathologically confirmed undifferentiated leukemia or biphenotypic leukemia Pathologically confirmed juvenile CML with or without either 7q- or infantile monosomy 7 Leukocytosis with absolute monocytosis greater than 450 microliters AND Immature myeloid cells in peripheral blood circulation Less than 25% marrow blasts Myelodysplastic syndromes: Refractory anemia (RA) RA with ringed sideroblasts RA with excess blasts (RAEB) RAEB in transformation Chronic myelomonocytic leukemia Pathologically confirmed stage IV lymphoblastic lymphoma No active CNS or skin leukemic involvement No consenting suitably HLA-matched related donor available Consenting unrelated donor available