Before upgrade to Windows Vista..

Seriously, think twice before u upgrade, o consider open, secure and free alternative Linux OS. Out of so many Linux distribution, I strongly recommends Ubuntu Gusty.
Here why:

• Needs goods reasons why Linux is better OS compare with Windows> looks here.
• It just work - Upon installed, ubuntu detected my all my devices, and install drivers correctly, this include my media card, wireless network, video, usb, and etc.
  
• Dell start selling PC/notebook with Ubuntu pre-installed, other vendor like Lenovo will follows soon.
• If u impressed Windows Vista offer "Wowo wow"3D desktop effect, well, looks what Ubuntu Gusty + Compiz offer:

• Linux could run Windows applications such as MS Outlook, PhotoShop, IE, even MSOffice (If u really really have to, but do consider use open office..) either via Wine (A windows emulator), or via Windows XP vmware image. User could create an empty OS image using VMware server (Free), and install Windows XP (Using legal Windows XP licenses, off course), and install applications on the vm image created.
  

Seriously, do u really have to upgrade to Windows Vista, post your doubts on my comments page, I am more happy to help here