I’ve been with 64Bit Linux with all userspace apps in 64Bit since Years now.
Windows and proprietary software crap vendors will still take years to migrate to full 64Bit-performance cause most apps are still sold as 32Bit and are slowed down significantly in the Windows 32Bit Emulation on windows 64, so there’s no use at all using windows 64 except for RAM access >2GB 
How many windows games are available as 64bit exe?
Look at the Adobe Flash proprietary incompetence. Forces all users in the world to use 32Bit webbrowsers, even on Linux, they just dropped support for the 64Bit-Player on Linux x86_64, leaving millions with a security exploitable old version plugin, Idiots 
I hope HTML5 will kill Adobe’s Flash security-hazard crap.