There seems to be a obsession with version numbers: People perceive these as if they must always have the latest/greatest. For example, when MSSQL 2008 came out, the database admin at a company I work for upgraded the MSSQL 2005 database to it, breaking a few applications due to incompatibilities. Version 2008 offered no features we were planning to use, so from an operational standpoint it was completely unnecessary. But it was motivated just because of the higher version number.
The same with Python2 and Python3. Python3 just exists out there so library developers can port their code over to it. It isn't meant to be used in production yet, and people learning Python are advised to learn Python2, not 3. Yet time and time again people choose version 3 to begin with 'because it must be better since it's 3 and everyone knows 3 is better than 2' (the most often heard reason on the #python IRC channel), thereby making it more difficult for themselves than necessary.
Python 3 is much more than a version number increment. Newbies are advised to use Py2 only because there are more libraries available for 2, and newbies are more likely to need more libraries. This is changing slowly but surely as more libraries go to 3.
2.7 is the last major release in the Py2 line. It's all Py3 from here on out, so people are starting to take Py3 seriously, as they rightly should. Python 3 is now the default distribution in Arch Linux and other bleeding-edge distros will be following soon. I'm kind of disappointed the major shift didn't start happening earlier, though the long cycle was to be expected.
"Stable" and "production-ready" Python 3 releases have been out for about two years now, by the way, so this definitely isn't a case of everyone jumping over just for a higher version number, and Python 3 has been "battle tested" for a while. I'm sure as the real heavyweights like Scipy start seeing real Py3 usage, cpython3 will get a lot of fixes and improvements.
We're just starting to hit "conversion critical mass" where everyone is beginning to see it's important to upgrade Py3 soon. I would guess in the next year most major projects will have ports underway if not completed, so the Python world will be undergoing a major transition this year, which may complicate things for a while but is for the long-term good of the community. :)
In my case, it's more that, when I learn a new language, I don't want to end up learning something that's going to turn into the next PHP 4 in a year or two.
(That is: still used, has lots of libraries written with it, technically more or less future-compatible, but is the thing everyone is moving away from.)
The same with Python2 and Python3. Python3 just exists out there so library developers can port their code over to it. It isn't meant to be used in production yet, and people learning Python are advised to learn Python2, not 3. Yet time and time again people choose version 3 to begin with 'because it must be better since it's 3 and everyone knows 3 is better than 2' (the most often heard reason on the #python IRC channel), thereby making it more difficult for themselves than necessary.