At work for windows/Mac machines I use Webroot, after an infection though I will run superantispyware or malwarebytes from an external media device (they seem to have a higher detection rate). I usually run a software side firewall like tinywall on Windows or littlesnitch on Mac just to see what's making requests in the background. Interestingly enough at work Macs receive a lot more detections per machine then windows boxes these days.