Everything, everything I mean everything in the very near future and on ward will be 64bit. Windows 64bit systems do run 32bit softwares in case you need that too.

Essentially the nature of the emerging software and the capabilities of these software to optimize the potential of improved hardware devices is dependent upon  advanced bandwidth available using 64bit, 128bit and 256bit systems as the electronic architectures are made available.

You gotta decide if your new machine will be part of the past or future.