I try and make it clear that my work is usually under some form of license. This is to clarify for other people who might wonder what license they may use my work with, and to evangielise license to the unaware. And to make sure people don't abuse my work, claim it as their own etc.
As an open source believer, my licenses are mostly OS. This is also so most people can benefit from my work. Over time the prefered license(s) have changed, but right now my choice is clearer:
For 90% my development work, as in source code, binary etc, the license of choice is AGPL, as in Affero Gnu Public License version 3. Previously similar work was often licensed under plain GPL.
As AGPL is very open souce and quite restrictive for business use, I do offer alternative licenses as default for some utility work, or as an option if people contact me for AGPL work. The alternative is then either LGPL or even Apache License. Some previous work has been under MIT license.
My none code work, as in flickr photos, blogs etc are often under some type of Creative Commons license. Always with attribution(by), most of the time with share-alike(sa) and sometimes non-commercial(nc). But rarely with no-derivatives(nd), as my view is to share and modify is good.
In addition I often append an optional ethical license. This tend to reflect my expectations on how people recognise and reward my work in regards to how much it is important to the people using it and how much resources they have. I usually use my own respect license.
Ps. This is work I do as a private person, often via flurdy.com. Work I do in my real job, is (unfortunetly) mostly closed proprietary source code.