I don't really think people hate Windows so much as they prefer something else to it. I can understand that because Windows has a monopoly and virtually every PC you buy has it on it pre-installed, so people just use that and don't bother trying anything else, but that doesn't mean there isn't something better out there.
We discussed stability and ease of use, but what about cost? $400 for the best version of Vista is not a good price... yes, it may seem cheap when you buy a PC and it comes with it, but it isn't free. Having it pre-installed adds a great deal to the cost, and I think other than the monitor Windows is the most expensive part of a manufactured PC.
I also like how virtually every piece of software on Linux costs nothing. I don't need to spend a ton of money on office software, or financial software, or anything because Linux pretty much fills every niche with free programs that are easy to install. I would really argue that they are much easier to install than on Windows, too. I just load up Synaptic and pu a check near the software I want, then click the install button and it automatically downloads and installs it for me.
Can Windows really do that? It can with IE and Media player and some other things, but can you download and install graphics editors or word processors to windows with one button click? I don't think so, so maybe Windows is actually the harder system to use. It certainly is far more expensive. Why spend money for Norton when there is free antivirus software like ClamAV? Linux saves you money.