I wouldn't go so far as to say that Apple Macs are better than PCs running Windows, but I'm a little biased anyway (typing this on a Macbook Pro).
1) the laptop itself
Apple laptops are made to their own precise specifications. Small things make them great like the slot-loading DVD drive, as opposed to the flimsy tray that most Windows-installed laptops come with. All the ports are on the sides, not the back, so that it's easy to connect stuff without having to turn the laptop round to see what you're doing. Brilliant screens. Built-in webcam. All that sort of stuff.
The bad thing is that because they use all their own hardware, you have to go with what Apple say. Although saying that, no laptops are particularly upgradable anyway.
2) software
Macs run Mac OS X. This is so much better than Windows, I wonder why more people haven't switched. There are no active viruses on it currently. There is no spyware. It has its own good firewall, you don't have to install a free one like Zonealarm. Its security features are light years ahead of Windows. It is based on UNIX, and as such is also much more stable than Windows and manages memory better. Case in point: I can happily leave my laptop on for weeks at a time without restarting, and it doesn't slow down.
Finally, at one point Macs were definitely better than Windows-based machines for doing design work. Now all the major important apps are also available on Windows, so it's a mute point really. Macs still have better colour support built-in, as well as much better typography, but this can be improved on Windows anyway.