You might find it advantageous to read up at these forums since they are laptop specific :
http://www.notebookforums.com/ http://forum.notebookreview.com/
As regards high spec. graphics, this really depends on what you will be using the pc for, and what your requirements would be.
If you're planning to run things like Half Life 2 - then you may well be able to have high settings and stull get decent fram rates ... but newer games like Crysis - you would only get middling frame rates even on average settings.
The 8600 GT is not a bad card, but the 8800 is a quantum leap ahead - and naturally they are still at a premium in laptops.
Cards that use system ram are not comparable to cards with dedicated memory since they are still juggling resources rather than being purpose built.
Read the forums above, look at their faqs regarding expected performance, and likely gains from tweaking, overclocking, or optimising drivers.
You should then have a better idea of what you're likely to see for your money.
Depending on your budget, consider these people as they have a whole cross section :
http://www.google.co.uk/url?q=http:/...EyY5GdsIEeURsg