I have a Macbook, and totally LOVE it. I used to have a dell laptop a year back. One thing that i miss about it, is just not having it. usually everyone that I know has a windows.

Mac:

Pros:
Stylish
no viruses, spyware, etc
Its fast
programs are SUPER easy to do
very easy to set up and use
6 hour battery life!
the macbook has a sweeet keyboard
you can install windows xp or vista on it and have both Mac and Windows on the same computer. for programs that arent compatible with the mac
macs version of office (iWork) is only 80 dollars compared to Windows Office's 150 dollars

cons:
not compatible with windows programs
you cant write(put anything onto) a portable hard drive used by windows computers
some online games, ect arent compatible with the mac (very few)

If you already have a dell computer, most likely you have the disc for windows. it is super easy to set up, so you can use windows programs that you have that arent compatible with mac.