I myself am still divided over whether or not to get vista. They've implemented quite a few security enhancements over windows XP. If I do get it I'll probably go 64 bit. There's a technology in the 64 bit version of vista which requires driver companies to have their drivers signed by Microsoft. In doing this it prevents malware from hooking in deeply into the kernel. Also from now on Microsoft is denying software producers the right to access the kernel. Right now there are already documents on the web that are showing how to bypass this.
Microsoft has plans to implement something which runs very low down under the kernel in the system, in probably a later version of Vista. Maybe Fiji or Sp1? (I hope so)
So right now it's just a deterrent but in the future it will be a "works for sure" solution.
You can listen to more about this on
Security Now 67
Also Windows Vista is named after a bar. Windows XP was code named Whistler which is a ski resort in BC, Canada. Blackcomb is also a ski resort. Longhorn is a bar between these Whistler and Blackcomb. I have an audio clip from a Windows Weekly episode in which I heard this. I also looked on google maps and there is a Longhorn bar.