Dedicated vs Shared Memory

[SageOfTheWabash]

This may not be as simple a question as it sounds. I am buying an entertainment/desktop replacement. I game a lot but this laptop won't be a dedicated gamer. I do a lot of audio and video work, plus I require a TV tuner.
I am unsure what Nvidia card to get; the 9650 with 1 gig of dedicated memory or the 9600 GT with 512Mb of dedicated memory and up to 2 gigs of shared memory? I had thought I would choose 4 gigs of system memory for Vista 64 bit, however the shared video indecision begs the question of using 8 gigs of system memory?

I am hopeful that some of you have solved this question, or at least have opnions.

Help Please.

 

[adweston]

Dedicated is faster than shared. 512 should be enough of it for most things though.

 

[SageOfTheWabash]

Thanx to you all for the great responses.