Google Talk

Could this be what Google is aiming for?
www.pulver.com/communicator

It is already compatible to the most popular IM protocols and has cross-platform VoIP:
www.pulver.com/communicator/geekzone.html

I guess maybe in a few months from now Google Talk will offer all of this but with a prettier face ;)
Basically the most important things that are missing are SIP compatibility and Mac and Linux clients, both of which are on Google Talk's roadmap. Once they are compatible to SIP you'll be able to use many different clients on pretty much any operating system anyway.

There are already SIP and IM clients for some mobile phones, so it wouldn't surprise me if they are also working on a Google Talk client for mobile phones. If they manage to finish such a client and work out contracts so a bunch of 3G phones ship with it pre-installed in 2006, they will have a killer application.

But I'm a bit disappointed they didn't include SIP compatibility from the beginning. Right now it is just another IM using an incompatible VoIP protocol. Most people I know who have a gmail account already have an IM account they don't want to give up, and they only use gmail to try it out - everyone already has an email account, and most people who like webmail have had a yahoo/hotmail/gmx account for ages.

People who use VoIP either use SIP or Skype. With SIP you can chose your own client, you can even get a hardware phone and use it without a computer. Skype is totally incompatible to everything else, so I'm guessing Google Talk will kill it sooner or later if Skype doesn't adopt open standards like SIP.

I wonder how long it will take until you can reach me at my FWD number with Google Talk! These are exciting times with new approaches to some still not completely solved problems (like better NAT traversal, encryption, etc).