The best course of action for the West is to contain and weaken ISIS but not to engage them directly.
There are more than enough military and financial resources in the region to defeat them without the West getting involved.
Do you know who you would direct your boots on the ground against.
In August 2013 David Cameron proposed to the House of Commons that the UK bomb the government side in the Syrian civil war. Today he is thinking of proposing to the House of Commons that the UK bomb the Syrian government's main opponent in that civil war.
The West hasn't got a clue about its own approach, never mind any understanding of the issues.
I's add to that the fact that while we know nothing about the bombing and subsequent ground force action in Fallujah in 2005 by the US Marines it is infamous in the region. It is so not juts because of the devastation of the civilian population due to the aerial bombardment but also because of the massive increase in childhood cancer in the city as a result of the depleted uranium used in some of those weapons. Source
We need to be careful who we kill.