I suspect we will need to know what you want to do with that new system.
You can buy some very powerful notebook computers today, however, for the same amount of money you can most assuredly purchase a more powerful desktop PC.
Heat dissipation is a very important aspect of the hotter CPU's and the higher end GPU's, and desktop systems provide a much more easily cooled environment.
If you have a need, even occassionally, to make use of the portability of a notebook PC, then it may make sense to look at one that may meet your current requirements and give you most of the best of both worlds.
The ASUS Model C90 series
, for example, has a DX10 capable video card and can handle Intel Core 2 Extreme processors.
It is almost a matter of what you want to do, and how many $$$'s (or equivalent) you have.