Get service from a SIP VoIP service provider, not Google Voice. Consider the very small monthly cost of the service, vs. your salary and benefits, and the risk of losing them if you eventually get "in trouble for" using unreliable phone service, and it's a no-brainer. Some employers will even reimburse you for the cost of your business use of your home phone.
Steve, thanks very much for your input. I've come to the same conclusion and have been browsing possible VOIP providers. One of the best features of GV, for my purposes, has been multi-line operation; that is, I can initiate or receive a call, then put that person on hold and initiate/receive a second call, and then combine/conference the two together if I want. This is possible with just one GV line. I spoke w/ PhonePower yesterday, and apparently they do not support this functionality. Would you happen to know of any VOIP provider that's able to do this??