there a basically several techniques discussed here, and like bram said, joomla has different ways to achieve the same thing or do things alike, but i prefer the v= param technique.
this can be done by editing (add)
/components/com_datafeeds/views/items/tmpl/default.php
(somewhere about)
line 15: disable the old $template line by #
line 16: $template=JRequest::getVar('v',$this->where);
i also planted the line 16 also in the if AND esle, just to be sure
now you have to make links like
/dagaanbieding?v=thumb
/dagaanbieding?v=list
or to make it sticky, it needs a bit more php coding in the default_thumb.php, default_list.php and so on, again, there a several ways to do so, you can place the data in a cookie, login profile, or retrieve it as a user session.