That notebook is basically the same as what I will probably be getting this summer. My brother has the 9300 and it is a very nice notebook. The decision to wait depends on multiple things. Do you want to play DX10 games? And can you afford to wait for mobile DX10 solutions? If you want to play DX10 games, then you are going to want to wait. Most laptop graphics cannot be upgraded(not certain about Dell). And unless you need to have a laptop right now, then I suggest you wait. Mobile DX10 cards are rumored to be coming out in the Spring/summer so the wait won't be too long. If you need a laptop now (which it doesn't seem like you do) then get something cheep that you wouldn't mind it not being used once Dx10 is released. Hope this helped.
If you want Vista and DX10 in all its glory, you are better off waiting till this summer. While the 7900 GS is a good card and will run Vista, it can not support DX10.
You are about to answer a thread that has been inactive for more than 6 months. If you still wish to proceed, please ensure that your posting is original and does not duplicate or overlap any prior responses to this thread.