I'll try not to be technical, but all the things I list are the things you'll find on a price tag at your local Best Buy.
14 inch screen
200-250 GB hard drive (trust me, it's very easy to fill a hard drive, especially if you like taking pictures and videos)
2-3 GB of RAM (any lower and the computer will run like a dead horse, any higher and you'll end up paying "an arm and a leg")
1.83 GHz processor or better (I prefer Intel over AMD, but AMD is cheaper...if you're on a tight budget...well...)
Integrated graphics - since you're not gaming, a dedicated graphics card is not needed
Windows Vista Home Premium (Ultimate is expensive, Home Basic is junk, Business is...for business)
If you want a Mac...try to get it used - new ones are quite expensive.
In my opinion, you should go bargain hunting for a Toshiba Satellite or HP Pavilion.
Careful with Dells - all my experiences with them have been bad. I have a 10-year-old IBM and it runs better than my 5-year-old Dell (not that I use either for anything practical).
Is it just me or did everybody here get at least one thumbs-down?