Here is a cool prospect: Skype and Google Talk become interoperable. That seems to be a possibility, according to Om Malik:
Just as exciting are our plans to explore interoperability between Google Talk and Skype, making it easier for our users to chat with one another. This is just another step in our commitment to interoperability via open, industry standards.
The Google Talk team posted an announcement about the Google/eBay deal on their blog and talked about their plans to "to explore interoperability" between the two clients. If this exploration comes to fruition it will be pretty exciting indeed and will probably mean I can cut my number of open clients down by half!