I kinda liked Windows Messenger/MSN/Windows Live Messenger with all its quirks.
There were even a few MSN apps for Android back then, like Epinephrine. It was nice. I could even use MSN from my Sony Ericsson W595 through eBuddy and Bluetooth PAN networking.
Sadly, Facebook killed it and for some reason, they thought it would be nice to kill it off in favor of Skype, which never worked as intended and was a really heavy boy to run.