Nice review of Skype and Google Talk. I'm using Google talk and find it to be nice and easy.
The only downside I see to both Skype and Google Talk is you are limited to chatting with one person at a time. I understand that it might be a technical requirement when you actually talk with somebody, but I often chat with 3 or more folks online. I'm keeping MSN messenger around for that purpose.
Google Talk is integrated with my g-mail which makes things nice and handy.