The Windows Messenger can do almost everything that the MSN Messenger
can. It has also the feature to attach to a live communication server,
that companies can run within their intranet. Windows Messenger also
looks cleaner and more straightforward, MSN Messenger has a more
consumer-in-mind design with nice colorful icons etc. You can change
the background, use a picture of yourself as an icon etc. Funny little
things that nobody really needs...
Your contacts are stored on a Microsoft server. So it doesn't matter if
you start MSN Messenger or Windows Messenger, you'll see all your
contacts anyway.
Windows Messenger is built into XP, so you can't really uninstall it
without also uninstalling other features.
So I prefer Windows Messenger. It's built into XP and I don't have to
install additional software.
The only problem is if your contacts want to do video chat with you. If
someone is running Windows 98 (therefore he's using MSN Messenger as
it's the only messenger for Win98) he won't be able to video conference
with someone using XP and Windows Messenger. So the XP side has to run
MSN Messenger too. But that's only for voice and video chat.
Keyboard-Chat is no problem. Frankly speaking I don't understand why MS
is producing 2 different Messengers that provide 95 % of the same
features but are not 100 % compatible.
Check this out for more information:
http://messenger.jonathankay.com