If a model release is needed, is determined by how an image was created and how the image is used.
A model release protects the model and the
publisher of the image. Sometimes the photographer is also the publisher.
A model release is not needed for display on a personal web site, but would be needed for a web site where you promote your photography,
IF , the people in the photos could be perceived as endorsing and/or sponsoring your photography business
and/or the photos were made under controlled conditions.
In some states, their "Right of Publicity" laws could come into effect.
Which brings up the point that a model release you snatch off the Internet, may not actually be vaid in your state.
Consequently, I would recommend you use a boilerplate release written by qualified attornys, familiar with the ins-and-outs of publishing and model/property release law.
Fortunately, on of those is readily available at:
http://contributors.gettyimages.com...SAMPLE_Model_Release_-_English_-_Dec_2008.pdf
Getty has their release available in a number of languages, and they also have a property release.