In the future I plan to purchase a 13" MacBook Air and a MacPro desktop.
I used to be all hardcore PC/Windows b/c I used to do a lot of hardcore gaming. My current Windows desktop has a GeForce GTX480 Tri-SLI setup with an Intel Core i7-960 overclocked to 4.2Ghz (liquid-cooled) & 12GB of RAM. It's a beast & will run any game at high framerates, but I don't game anymore, so it's kind of a waste.
A basic MacPro with a Radeon HD 5870 & 8GB of RAM will be plenty enough for me. Besides, I can run Boot Camp & still use Windows 7 when I need to run some strictly Windows applications.
The MacBook Air just looks sweet & is very thin and portable with a long battery life.
iTunes & the iphone in general seem to be much better suited to MacOS X. They just seem to integrate seamlessly with no issues. iTunes 10 seems to crash a lot on my Windows 7 desktop, but does OK on my little Acer Windows 7 notebook...weird.
I'm more a less done with Microsoft, I did have a Zune HD 16GB & it wasn't all that great and app selection is horrendous...12 apps or so lol. All they have is Twitter, Facebook, and the rest are lame-o games. Besides that, Zune marketplace is overall great. With a $14.99/month Zune pass you can d/l unlimited music. I kept my Zune software & Zune pass subscription for this reason. I d/l songs from Zune marketplace, strip the DRM using Sound Taxi, convert the .wma's to AAC, then transfer to my iphone.
Microsoft should just stick to what they do best, operating systems, office suites, and gaming consoles.