$3000 is a lot of money and can get you a very high end computer.
I personally have been looking for a new machine and have
almost decided to go the laptop/note book route.
I found this:
http://besttop10tip.com/top-10-best-gami...s-in-2013/ and have been meditating on it for a while.
That is under $700 you are setting a much high price range which pretty much gets you most any device you can have your heart set on.
Are you brand loyal? I like Gateway - because the box is in the color of "Cow" - No more seriously because every gateway computer I have gotten ran very well and the gateway folk we far, far more customer friendly than Hewlett Packard or Compaq. If so find their website and look at their machines.
I have always wanted an Alienware:
http://www.alienware.com/
These are/were considered top of the line gamer computers.
Here are Alienware laptops:
http://www.alienware.com/landings/laptops.aspx
I assume that you have games - how many of those you want to play may determine what it is exactly you want in the way of graphics which is the ultimate deciding feature for most games.
I would look at the system requirements lists of your games and see which graphics chip/card is compatible/optimal for the majority of your games.
The thing you may want to seriously consider here is that a top of the line computer only remains top of the line for about 2 years. Every two years (thereabouts) the next generation of processors, graphics cards, sound cards etc comes out. Investing $3000 into a machine that is only going to be 'worth' it for two years may be a bit outrageous.
Thus maybe you will want to lower your price range a bit?