I have been told that if you upgrade from Vista to Windows 7 you must reinstall all your software. Is that true?
This is only true if you wipe your hard drive clean and do what is called a "clean install." Otherwise you do what is called an "in-place" upgrade/install and you don't have to re-install your programs.
I did an "in-place" upgrade after weighing all the pros and cons (for my case, I could easily have done either one) and I had no problems. I'd recommend that if your system is in good shape to begin with.
If your current system has not been kept in top working condition you may be happier if you wipe clean and install from scratch although it will take many hours longer to do so.