I have been using Google Voice for a couple weeks now, and the more I use it the more I like it,one HUGE benefit I see is that when I start getting spam calls from my google number you have the option of routing those calls to special "voicemail" I like to call it the trash.
Another great thing is I can use my Ipod Touch to send and receive messages (in wireless hotspots), which means no more typing using my cellphone (not a keyboard, lets just leave it at that).
So I've been trying to come up with some ideas, I realize now that if I can manage to mashup my Google Calendar (Birthday event reminders), and Google Voice, I can now send Happy Birthday Texts automatically, and send myself a reminder that I did so....how cool would that be.
For those of you wondering Google Voice is kinda like having a central call center (one number) that can route different kinds of calls to different places, very convienient.
On the plus side I had all my google contacts in order (because I lost my enV back in the winter snowboarding), and because the iPod Touch can sync with the contacts and calendar I was set when I signed up, so now it's a simple search for a contact, then click call or sms, and if you call, it will prompt you for which phone to call from, so what it will do is call your phone first, then start the ringing for the other phone (kinda like a "transfer"), SWEET.
Anyways, the more I play with Google Voice the more I like, I'll try to continue a review at some point in the future!
Biggest drawback though at this point is that GV won't accept MMS messages.
I'll update if that changes