Have tried and used quite a few, Avira, McAfee, Avast, Webroot, S&D Search & Destroy, Trend Micro, the list goes on.
Then MSE came along, haven't looked back since.
Although there is one that's moving up the ladder quickly and knocking the socks off the others including MSE, AVG, ESET, Norton, Kapersky, etc: and that's Vipre Home Premium.