Macs and PCs both have their good and bad points.
Macs: Good points- Easy to use
- Have a good range of software
- Are excellent for any kind of graphical work
- Can read/write PC format disks if necessary.
- Crash rarely
- Fewer viruses
- Under OSX, security is better than Windows (even XP).
Macs: Bad points- Range of software is limited compared to PCs
- When they do crash, they can do so in style and require unplugging (Under OS 9 this happened surprisingly regularly, but OSX doesn't seem to suffer from this).
- Under OS9, security was, frankly, crap.
PCs: Good points- Huge range of software.
- Later versions of Windows are almost as easy to use as the Mac
- Later versions of Windows are fairly reliable.
- While Macs do multimedia stuff (audio/video/graphics work) better, pcs do almost everything else better. Thats is not to say that the Macs cannot do other things (in fact, I know people that use Office for the Mac and swear it is far better than Office on the PC).
PCs: Bad Points- Viruses. Whether the amount of viruses/trojans out there for Windows is a sign of bad security or just an indication that many more people use PCs, the fact that the viruses/trojans are there is bad.
- Windows can crash spectacularly.
TBH, generally, you can probably do anything you need just as well on both, so either should be OK for your needs.
PCs tend to be cheaper though..