Back at the last UDS Orlando summit I mentioned that Canonical was looking at finally recomending the 64-bit version of Ubuntu Linux by default for new installs rather than 32-bit. This issue is again being discussed at the last minute for the Ubuntu 12.04 LTS "Precise Pangolin" release due out next week.
The Ubuntu 12.04 LTS 32-bit release will obviously still be available for older hardware that doesn't support Intel/AMD 64-bit, but the "recommended" version of Ubuntu Linux that will be the default on Ubuntu.com, when ordering Ubuntu CDs, and for Ubuntu USB drives bought from the Ubuntu Store is looking to be 64-bit. Steve Langasek resurrected this 64-bit discussion on the ubuntu-devel list on Monday.
With the Ubuntu multi-arch situation being cleared up, most applications and plug-ins now working fine on 64-bit (such as Adobe Flash and Java), and 64-bit being usually much faster than 32-bit, there really is no big reason not to move to the x86_64 version. Using 64-bit software can lead to higher memory usage, but that's about the only potential downside. In response to Langasek's mailing list message, some Ubuntu developers have been overly concerned about 32-bit netbooks being out there still and for systems that only have 2GB of RAM where using x86_64 software may lead to running low on memory and thus increased SWAP usage...