Im a former Vista User 64 and 32bit. I just installed Windows 7 and there is not a hick-up. I primarily use FSX and everything works awesome on it. As a matter of fact Im getting better performace with Windows 7.
The main difference between Vista and Windows 7 is that it does not hog your computer down. It boots up faster and applications run quicker and smoother.
You can use vista and I have no reason why you shouldnt....but windows 7 is the way to go and things will only get better as time progresses.
On Windows 7 the only slight issue that I have seen is that Adobe flash player is only compatible for 32 bit systems currently, BUT if your using a 64 bit version there is an option to use the 32bit player and it works just fine.
I like to keep up with the current trend for OS's. Windows 7 is really full of additional user ease features as advertised on TV.