Before being bought out by Microsoft, a lot of my co-workers bought stuff from Apple (mostly mac laptops, but also iMacs). I recently bought an iBook second hand, but in my team of 8 people, 4 have bought new Macbooks in the past 4 months. A few people from other departments have also bought them. I happily encourage everyone to do this and have been urging the other holdouts to do the same.
Now, you may be thinking why somebody from Microsoft would be encouraging people to buy Apple stuff. Isn't that a conflict of interest? Aren't they competitors? In the olden days (pre-2006) perhaps, but not anymore. Macs are capable of running Windows thanks to boot camp, and indeed, that's what a lot of my coworkers do. In fact, they run Vista and Mac OS in parallel (ie, they can actively switch between one and the other). Macs have also been able to run Microsoft Office for years. So, now, people can buy Macs and run Windows on them, and run Mac stuff on them. There really isn't any reason to avoid getting the Mac.
Microsoft and Apple are not pure competitors now, at least in the OS market. Apple still makes computer hardware, while Microsoft does not. Microsoft software now runs on Apple stuff, and while not vice versa it doesn't really matter. Zune and iPod are competitors, sure, and Windows Mobile and the iPhone will be competitors, but for now the distinction as pure competitors on the OS side is blurring. So, when I encourage people to buy Apple stuff, I'm really encouraging them to buy Apple computers and install Microsoft software on them.
Of course, when I encourage people to buy Macs, iPods and iPhones, I really do have an alterior motive - I own shares in Apple. My co-workers' need to fulfill their spending urges on tech stuff ultimately makes me money! I own shares in Microsoft as well -- as you can see I am playing both sides. It's like I'm the Emperor in Return of the Jedi.
Oh, now go buy an X-Box.