Now, I don't normally gush about such things, but the new Gmail-Google Voice integration, which allows you to make and receive calls directly from Gmail for free(!), just pretty much made my head explode. A lot of companies are going to want to ditch their landlines and go virtual.
I've been playing around with the new service and, as long as you have a half-decent headset, it's pretty much flawless. The best thing is that you can set it up so that Google Voice will forward your calls to other numbers if you don't pick up--or if the call comes during certain hours. Oh, and the Google robots automatically transcribes your voicemails (albeit comically).