let me start by saying that vista looks like a very nice system.  it is graphically beautiful, and seems to be much more user-friendly.  i can see many more security options, and some more built in security.  if you look at your computer as more than a simple utility on your desk, you probably value the pros that this offering will bring.

the cons are few but important.  if you use your computer for anything other than the largest most main-stream software applications you may have problems with software support.  microsoft has made a tool available to determine if you are okay to upgrade, but im not sure how much to trust it yet...  if you install now, or anytime in the next 6 months you will probably run into software that will not run, or will require expert help to install.  then there is hardware, out of the box vista supports a ton of printers and other peripherals but if you happen to have a printer with no vista drivers, it could be months before you are printing.

the price tag is reasonable for what you are getting, i get oem versions online of vista ultimate for $200, but you may need more hardware to get it running as fast as your windows xp machine. 

after that bit of information i recommend to everyone to wait around 6 months to upgrade but there are definitely a few people who will want it right away, and for them i am here for you :)   - give me a call and tell me your system specs and ask any question you may have in person