I agree with Bald_Monkey; Excel 2007 is very good. I used to use combinations of Datview, Biomed, Prism and Fig.P to get decent graphs, but they were unbelievably time consuming and prone to error (and very old), and the significance asterisks were a pain to get in the right area. I just use Excel 2007 now, it's much simpler and quicker and you can get SD and SEM calcs in a flash. The graph software can be easily customised too, which can 'distance' your representation from a Microsoft application if you want to. Best of luck!