Some of the greatest achievements Vista brought were what annoyed people the most. The new driver model was great, but a lot of older devices wouldn't work as well; DX10 was, while underused, many times better and more efficient than DX9; UAC, while annoying, teaches users about what sorts of actions might pose security risks (and also encourages software developers to write programs that don't require elevation). While it's kind of sad Vista wasn't more appreciated than it was, it did let Linux become a lot more mainstream (Linux usage just passed 1% for the second time in history about a week ago; the first time was earlier this year). The development that has occurred in terms of Linux usability over the past few years has been utterly insane, and I think the open source community has really benefited from it.
Also, of course your network is going to get viruses if you're using IE6. You can have the strongest virus protection in the world and extremely well-designed security policies, it still won't matter if your browser software can be exploited to modify the system. IE6 was insecure when it came out, and virus-makers keep finding better and easier ways to exploit it. It may be a pain to upgrade an entire network of computers to IE8 or Firefox, but it's a necessary pain. My old high school hasn't used IE6 in years, and in the four years I went there (and the two years I've been out), they've had no virus problems whatsoever.