If you are writing free software, choose your license appropriately. This can make a big difference with respect to adoption of your software.

I’ll just show you an excerpt from a Debian changelog:

* DFSG version of Mono 1.9
  + Deleted the mcs/class/System.Web.Extensions/ directory as
    mcs/class/System.Web.Extensions/System.Web.Script.Serialization/JSON/*.cs
    is licensed under Creative Commons Attribution 2.5 which is not
    DFSG-free.

Debian policy doesn’t allow us to include Creative Commons Attribution 2.5 in the main Debian archive, since that license doesn’t meet the Debian Free Software Guidelines, which are part of our social contract. Therefore we must and will remove such code.

debian-legal summary for “main” Creative Commons licenses

Creative Commons is aware of these issues:

Creative Commons recommends and uses free and open source licenses for software.

And then they suggest to use GPL. While there is a link in the right side menu to the Creative Commons page on licensing Software, they IMHO don’t make this obvious enough. Their license chooser should include a central link “if you intend to license software, read this”.

Creative Commons even includes “wrappers” for common licenses: CC GPL, CC LGPL, CC BSD

So if you like Creative Commons because of this pretty “commons deed” human-understandable version of the license they offer, just use these wrappers. The “legal code” links will actually take you to the GNU or Opensource.org license pages.

I’m not aware of a good reason to use an opensource license other than GPL, LGPL or 3-clause BSD, depending on how you want to allow your opensource code to be used in combination with non-free software. If you are contributing to a bigger project, choosing the same license as the main project is although a very good idea.