I am disappointed that Dell doesn't support their systems by providing updated drivers throughout the warranty period (even the initial 1 year period). I can save some people the time I wasted trying Win7 x64 drivers for my Dell Latitude D630.
for the chipset software, I used the package downloaded from Intel.
For the intel wireless card, I used the driver downloaded from Intel. (Thanks for supporting your stuff, Intel!)
Windows is using a generic driver for audio, but I expect a better one is available. Some people have reported problems with the Dell provided Windows Vista driver audio-A09-R171788.exe so I didn't try it.
Windows Update did provide a basic bluetooth driver for the 360 module, but I also suspect a better one is out there.
Windows Update also provided a driver for the O2Micro smartcard reader.
Windows has built-in drivers for 1394 device, and the broadcom 57xx ethernet controller, and the O2Micro CardBus controller.
Fortunately Dell doesn't change the Latitude series very much, even from D-series to E-series. Often drivers for the newer model will work on the older model. I AM able to use the following E6400 Win7 64bit drivers on my D630: