I suggest checking out the Apple Refurbished Store... the computers are sold with the same warranty as new ones and you can save several hundred dollars. I bought my 24 inch iMac this way last month ... the $1799 (new price) computer was sold to me for just $1299 including everything you get with a new iMac except the fancy box. (Rats, I just checked and the model I bought is now available for just $1199! But then, they have also dropped the new retail price.)
They currently have a refurbished 13.3inch 2.1GHz MacBook (White) for just $849.
If you have a student or a teacher or anyone someway connected to education in your family, then you can shop the Apple Education Shop. That shop offers discounts on Apple products for around a 10% discount or so.
Thanks for the suggestions...