What is the official "preferred" way to install pip and virtualenv systemwide?

If you can install the latest Python (2.7.9 and up) Pip is now bundled with it. See: https://docs.python.org/2.7//installing/index.html
If not :
Update (from the release notes):

Beginning with v1.5.1, pip does not require setuptools prior to running get-pip.py. Additionally, if setuptools (or distribute) is not already installed, get-pip.py will install setuptools for you.

I now run the regular:

curl --silent --show-error --retry 5 https://bootstrap.pypa.io/get-pip.py | sudo python

Here are the official installation instructions:http://pip.readthedocs.org/en/latest/installing.html#install-pip

EDIT 25-Jul-2013:
Changed URL for setuptools install.

EDIT 10-Feb-2014:
Removed setuptools install (thanks @Ciantic)

EDIT 26-Jun-2014:
Updated URL again (thanks @LarsH)

EDIT 1-Mar-2015:
Pip is now bundled with Python

http://www.pip-installer.org/en/latest/installing.html is really the canonical answer to this question.

Specifically, the systemwide instructions are:

$ curl -O http://python-distribute.org/distribute_setup.py$ python distribute_setup.py$ curl -O https://raw.github.com/pypa/pip/master/contrib/get-pip.py$ python get-pip.py

The section quoted in the question is the virtualenv instructions rather than the systemwide ones. The easy_install instructions have been around for longer, but it isn't necessary to do it that way any more.

This answer comes from @webology on Twitter:

$ sudo apt-get install python-setuptools$ sudo easy_install pip$ sudo pip install --upgrade pip virtualenv virtualenvwrapper

My added notes:

• On Mac/Windows (and Linux if the apt repo is outdated) you'd replace the first step with downloading setuptools from http://pypi.python.org/pypi/setuptools
• On Windows you'd have to omit virtualenvwrapper from the last step and install it manually somehow. I don't know if there's a way to do this without Cygwin, but I hope so.