Skype unfortunately the current industry standard, and the most important thing about messengers is a combination of accessibility and userbase. Skype easily leads in both of these, but I can't say the same about their secondary features...
[SIZE="1"]I do sincerely miss MSN messenger.[/SIZE]
Anyways, I just can't use KIK or mumble. My only picks at the moment are google hangouts and skype, though reluctantly. *shakes fist at google and microsoft*