I am not much of a Mac fan and I try to use them as little as possible so I can tell you more about the good and bad things about a PC than I can compare the Mac and the PC:

The Good:
1. Lots of PC makers give you a lot of choices on the manufacturer (Dell, HP, Sony - the Vaio has always looked very sexy, Alienware, etc.)
2. Faster hard drives, faster video cards and easy to customize with more storage space (especially a PC laptop with 2 hard drives), more RAM, upgrade the wireless card, upgrade the video card, etc.
3. Cheaper, and many times free, software for things like making backup copies of your DVDs or ripping a DVD to your computer so you can store it there instead of carrying your DVDs around.
4. The option of Windows XP is still available on many PC laptops
5. Option of a Blu-Ray or HD-DVD drive (now or even add on later)
6. GAMES!
7. Option of built-in wireless broadband cards (or PCI slot) so you can have the Internet in more places

The Bad:
1. Windows XP and Windows Vista 32-bit do not support addressing of 4GB of RAM (4GB looks like 3 or 3.5GB)
2. Customizing can get very expensive if you customize through the PC manufacturer
3. Too many games and you might not get your homework done...

Technically, OS X can't address 4GB of ram properly either, as it was 32 bit for the longest time and I think only recently have they actually taken advantage of 64bit processing. But, if you did have a 32 bit Mac, the kernel does a much better job of memory management, and you would still have access to all 4GB of memory with little trouble, unlike windows.