Monitoring software on the PC is OK as long as you don't give your employees or kids administrative rights. Restricted, user level permissions should be the rule otherwise they could indeed circumvent or outright disable the monitoring. Also, if you have a laptop that can be used away from your content filter, you would need locally installed software to have successful monitoring.
There is another software package that I didn't mention, called Systrack from Lakeside Software, that I personally had deployed on several thousand clients with great success and no circumvention. However, for a small medical practice, I think that the SpecterPro would be more advisable as it is easier to deploy and gain useful reports.
