The Google Talk Gadget is clearly more usable than the stand-alone GTalk desktop client or the floating AJAX version in GMail.
Here,
each chat session opens up as a tab (like Firefox browser tabs), it can
show previews of images or video and the chat client can easily be
embedded inside webpages.
There's however a small problem - while
we have browser windows in front of us all the time, the same may not
hold true for the webpage (like the Google personalized page) where we
have embedded the GTalk gadget.
So here's an alternate option -
put the Google Talk client in the Firefox sidebar so it always stays in
the foreground no matter what website you are on currently.
To add Google Talk to your Firefox sidebar, bookmark the following URL (right-click and choose Bookmark this link)
talkgadget.google.com/talkgadget/client
Now
goto Bookmarks menu, navigate to the above bookmark, right click and
choose Properties. Tick the checkbox that says Load this bookmark in the
sidebar.
Update: An employee of an investment bank confirmed that their organization
has banned Google talk in office but using the above method, he was
able to circumvent the GTalk ban and could chat with friend out the
firewalls of his office.
Google Talk gadget will always open in the Firefox Sidebar.