It seems NVIDIA has done everything right with the GeForce 8800 GT. The card offers plenty of power for all games, even at higher resolutions. Thanks to the 65nm fabrication process, the GPU has a lower heat output which allows the use of a cooler that uses only one slot. However it tends to be a little bit noisier than the other GeForce 8800 cards with dual-slot coolers.
NVIDIA has not only done a great job in building a fine card, but it is also sold at a very affordable price point. Personally, I would never spend more than 300$ or so for a video card, if a game is good it will be lots of fun on slightly reduced details settings too. Even though the price is great, ATI has a new product coming up too and if everything goes like in the recent past, ATI will offer their product cheaper than NVIDIA.
Last Friday NVIDIA issued a new SLI driver to reviewers which enabled SLI on the 8800 GT. Since this is the first set of released drivers, SLI is not running that good yet on the GT. But I am confident NVIDIA is working hard on this and can resolve the problems in short time.
The support for PCI-Express 2.0 and the lack of DirectX 10.1 are both so unimportant for the near future that they should not affect your buying decision. What is more important for the Media PC segment is that there is no HDMI+Audio support out of the box, which ATI does have. Other than that I really can't find anything wrong with the card. Let's hope there is enough stock to satisfy the huge demand that will be there for this card.