PC World has posted its list of the 15 Biggest Tech Disappointments of 2007, and Microsoft's Windows Vista operating system ranked at the top of the list. Here's what PC World had to say about the OS: "Five years in the making and this is the best Microsoft could do? No wonder so many users are clinging to XP like shipwrecked sailors to a life raft, while others who made the upgrade are switching back."

Mac owners and even some XP users love to bash Vista. The truth is - in my opinion - that although Vista has had a rocky start and definitely has its flaws, it isn't such a bad platform and it's going to supplant XP eventually. Microsoft wasn't alone on the list, however, as PC World was also disappointed with AT&T's broadband service for Apple iPhone, Mac OS X Leopard, Facebook's Beacon ad system, Amazon's Unbox, among others. You can visit PC World's website to read the reasons why each of them made the list.