I have to say very happy with Windows 7 Pro. I was able to get Ninja Trader 6.5 to work on it, and will try Ninja 7.0 in future.
I was able to get it to print through the network to a printer attached to a Windows XP computer through USB by downloading the Windows 7 drivers for that printer. Note, I have found that Vista does not print through a Windows XP computer, and the only way to get Vista to work, is have the printer directly connected to a network.
I have to say I like Cannon since they do have Windows 7 drivers for their multifunction laser printer/fax/copy/scanners.
The speed is amazing. I would advise anyone who is trading to get the Windows 7 pro. Also, if you are getting a laptop like I did myself, the main thing I would advise is make sure you get either ATI or Nvidia at least 512 dedicated video memory, I am using ATI and a quad core. Also, Bluetooth is good if you want to connect some items wirelessly.
My specs:
Dell Studio 15 laptop
DVD burner
Intel Core i3 2.1 Ghz
4 GB DDR3 memory
Win 7 pro
camera
ATI 512 MB Radeon HD 4570
Dell Bluetooth
Intel N wireless network card
320 GB HD