If you need to interact directly with the DOM element, why not just use
document.getElementById since, if you are trying to interact with a specific element you will probably know the id, as assuming that the classname is on only one element or some other option tends to be risky.
But, I tend to agree with the others, that in most cases you should learn to do what you need using what jQuery gives you, as it is very flexible.
UPDATE: Based on a comment:
Here is a post with a nice explanation: http://email@example.com/msg04461.html
$(this).attr("checked") ? $(this).val() : 0
This will return the value if it's checked, or 0 if it's not.
$(this).val() is just reaching into the dom and getting the attribute "value" of the element, whether or not it's checked.