From what I can tell, the CM paste is fairly generic. Since you are fairly inexperienced I recommend MX-2:http://www.newegg.com/Product/Product.aspx?Item=N82E16835186020
Not electrically conductive, no cure time, and performance that matches Arctic Silver.
I use AS 5, but it's a bit old fashioned. Like insisting on an all copper heatsink, it's just unnecessary and an inconvenience.