I am making my first attempt at building my own computer. It will be dedicated to gaming and will be equipped with a 56k modem so that I can download updates for the games. (I do not have high speed internet where I live.) I've decided to use Windows XP due to the fact that Vista is still in it's infant stage. However, there are so many choices that I'm not too sure which version of XP to go with. Home, Professional, Business, or Media Center. What about 23 bit vs. 64 bit? Also, is there a major difference in the OEM version versus the Retail version? (I do qualify for the cheaper OEM.) Thanks!