Apple have released some new ads that has a few good points that encourage people to "Get a Mac":

1. It just works.
2. You can make amazing stuff.
3. Design that turns heads.
4. 114,000 Viruses? Not on a Mac.
5. Next year’s OS today.
6. The latest Intel chips.
7. Instant video chats.
8. More fun with photos.
9. One-click websites.
10. Amazing podcasts.
11. Rock star tunemaking.
12. Hollywood-style movies.
13. No hunting for drivers.
14. Awesome out of the box.

I agree with these points - they are why I use a Mac too.