There are a number of reasons a user would want 64-bit operating systems and programs. It also explains the reasons for choosing one way or the other and walks through the steps to determine if your current operating system and/or DAW is 32-bit or 64-bit.
The following article helps to clarify the differences between 32 and 64-bit operating systems as well as between 32 and 64-bit programs. In the world of computing, the differences between 32-bit and 64-bit anything can be quite confusing.