Bob,
Thanks for the input. It's always good to get another set eyes on a problem / nuisance such as this.
Yes, you guessed correctly. This is a Windows system which I use for development / technical processing. (Windows 8 Pro, 4.1 GHz i7 3930K (6 core HT), 32 GB quad-channel Memory, SSD storage -- it's plenty fast for most things.) I keep it pretty clean with respect to unnecessary start-up programs and services.
I did try disabling the anti-virus software. (Good guess, I had not thought of that.) Unfortunately, it made no discernible difference in the required delay before being able to successfully start the Serial Monitor after a Sketch upload.
John