Ditto what the others said.  Don't even consider getting a laptop that doesn't have a TFT (also known as "active matrix"

 display.  Get a slower processor if you have to save some money, but for the love of God don't subject yourself to the horror of a passive screen.  Seriously, you'll kick yourself every time you turn the beast on if you didn't get TFT.  You'll think, why oh why am I so cheap, I was already spending a pile of money, why'd I have to skimp on the one part I have to look at all the time and can't change?  Woe is me...
That's pretty much all you need to know.  Unless you meant technical differences...