I'm thinking of switching to a 64-bit OS but was wondering if anyone else here is currently using one?

I want to do this so I can upgrade my main PC to 8GB of ram for video editing and post production work. However while I know that most 32-bit software should run perfectly well in the 64-bit version of the OS, what I'm wondering is if anyone using a 64-bit OS has had any compatibility issues with games or other software?

Also is there a list anywhere of games and productivity software that directly supports 64-bit? That come with (or has downloads) of 64-bit compiled versions?