Microsoft Messenger for Mac is known for being a program that runs fast, is extremely user friendly, and has a design Windows Live Messenger can weep over.

Messenger for Mac 6 is excepted to be released in early October with many new and exciting features, despite having a major update just a few months ago. Yahoo! Messenger integration has been added, and yes it has a few Windows Live tags placed around the place, but no name change is happening. iTunes integration has also been added, allowing contacts to view the song you are currently listening to, and other various tweaks have been made to how the program runs.

However, the two most requested feature are still missing. Video and voice chat have still not been integrated. These features have been requested for many years now, however Microsoft has now provided an explanation and said it would be added in Messenger for Mac 7:
Still Messenger for Mac has a few things better than Windows Live Messenger, the program now comes with a great new emoticon system allowing custom emoticons (as available in Windows Live Messenger) and spell checker feature:

The release looks very exciting for Mac users. The program has been criticised in the past for being neglected, but we can now say it is giving Windows Live Messenger a run for its money. It seems like things are getting better for Mac users.

>> Source & screenshots: APC

Subnote by the andyman If you can't wait until version 7 for video chats then aMSN, a free MSN/Windows Live Messenger client, includes webcam support and best of all is available for Mac OS X (as well as Windows, Linux and FreeBSD) - download here.