KieranD: In another application I was able to filter my contact list by open activities
On the Customers and Contact List screen there is a Filter By View option. There is no default filter here for Customers with an activity because the Activity screen covers this information, however, you could add another filter to the Customers and Contacts List to have this information if you wish.
KieranD: Can someone recommend a report that may be close to what I am looking for that already exists.
Under the Activities tab you'll see a list of all activities in the system based on the filter view selected. In additon there is an Activity Calendar link which allows you to view activites by user, by date range. There is no specific activity report but that's not to say you can't create one specific to your needs.
~C