Google Talk is dead. Long live Google Hangouts!
Google Talk was nice... Hangouts are better. Unfortunately I still interact with some groups of people who are using the Google Talk desktop client to manage chatting over their google apps accounts. The reason for this is that there is no native desktop client for Google Hangouts - thus, the initial hangout interface had to be accessed from a google site page (G+, email, etc). As Talk was being used, those people seldom had those site pages up, so they would routinely missed video calls from me - Talk does not seem to allow easy access to the hangout video calls.
Thankfully, Google heard the people's cries. They created an extension to Chrome which gives desktop like access to Hangouts - meaning you don't have to be on a google page any more to access hangouts features! It even seems to include Google Voice dialing now, which reportedly it did not at launch. You do, however, need to have an instance of Chrome open, however. You are using Chrome though, aren't you?