One of my favorite (and free, ahem) IM solutions (Google Talk, AIM, Yahoo, VOIP) is Octro as I have always found it easy to use and streamlined for simple use--plus the plugin is nifty.
Getting updated to 2.0, the Octro team has added some cool new features including
- P2P Video Conferencing (!)
- Complete VOIP product. Access to PSTN (something which was discussed in a recent podcast)
- Buddy Icons
Obviously the Video conferencing is the big one here. We'll be giving it a spin here at WME headquarters this week and let you know our thoughts. Chime in with yours in comments.
(Quick note: you need to have at least one Google Talk or Jabber account logged in before Octro will let you set the other stuff up! Download their manual from the above link to find instructions)