Last week, I received a complimentary signature copy of Windows 7 Ultimate from Microsoft. I think right now in Australia, it costs around AU $400-$470. I installed with x64 bit version replacing my erroneous Vista version. It has cool features, performance wise better than vista. The beauty is it will recommend with possible drivers and updates on install where as vista doesn’t(manual install). I haven’t encountered any errors and compatibility issues, loving it.