Petrie covered my complaints with Vista in a nutshell right now.
The Only reason I would upgrade to Vista is if my new programs were no longer compatible with Windows XP (this happened to me with Windows 98. By the time I was "forced" to upgrade to XP, XP was working nicely).
I would be much more likely to upgrade to WindowsX64 (the 64-bit version of Windows XP) as opposed to Windows Vista in the near future. I am in dire need of 64-bit memory addressing for my audio software but I lack both hardware and software support for 64-bit on my main system at the moment.
In short, "memory addressing" refers to how much memory (physical RAM or virtual paging file) that a single application can access, and how much memory is accessible in total by All of the applications running on the computer. In 32-bit Windows XP, a single application can normally access 2 GB of memory. This can be changed to 3 GB by altering the boot.ini file, which I do, but this alteration causes some instability in some programs. The total amount of memory accessible by Everything (including applications and the operating system) in 32-bit is 4 GB.
In a 64-bit operating system, this 4 GB total limit is extended to at least 128 GB. This allows one to install basically as much RAM as your motherboard will accept and every bit of it is accessable. While most people don't need more than 2 or 3 GB of RAM, I'm finding RAM to be a very valuable comodity for my audio stuff. I can fill 3 GB of RAM amazingly fast and get "out of memory" errors much earlier than I'd like to see.
For now though, Vista isn't the answer. I have little faith in it at the moment but hopefully a service pack or two, as Petrie said, will bring it to life a bit more.