Macs are expensive because they have low competition. People who work at a place that use mostly PCs will buy a pc and people who work with apples (most commonly school) will buy a mac. This mainly because of how much more compatible the os's are with each other. Thus apple can continue to thrive because people are forced to work with them or people are willing to pay the extra money for a cleaner os and free software.
A bad thing about apple is how poorly compatible they are with pcs, which are much more common than macs. They also require special software that only work with apple. Therefore using a program you purchased for your pc is not going to work with your apple. For example, you can't get Adobe Premiere PC disk onto a mac unless you get the new intel macs with boot camp, or virtual pc.
Nice things people have noted about apple would include the cleaner os and it's reliabilty. Apples also look very appealing, at least to me, and give off a professional look. They have creative features on their notebooks such as the two finger scrolling or Front Row. Their new Intel machines have a feature called Boot Camp which allows you to use Windows on an apple. If this feature is perfected and the flexibility of an apple is better (almost non-existant bios), the intel macs will be the machines of the future.
It all comes down to want you want to do with your notebook. If your surrounded by pcs, go with a pc and vice-versa. If you're a gamer, pc. If you work on graphics, music, or videos with the notebook and apples at your workplace, apple is the only way to go. I find editing programs on apple filled with features, though unflexible. I myself am still on the PC side mainly because of it's compatibilty and "able to rip it to pieces and upgrade it"-ness.