Which VOIP software for do you use?

[usta]

Skype is probably the most used VOIP software, especially for voice calls.
I was wondering if anyone is using other software, like Windows Live Messanger for video calls?
What do you use and why?

 

[The Howling Wolves]

I use Skype and haven't had any problems.
WLM ,on the other hand, has been a headache for some members.

 

[usta]

I've created accounts and tried to call the same contact using Skype, WLM and Google Voice/Talk.
Only Skype worked without issues...

 

[BugOutMachine]

magicJack

I use magicJack and it's great. I plugged it into one of my wall phone outlets and now every outlet in the house works. I also am able to successfully send and receive FAX transmission although it's not officially supported.

I use Skype for video chatting but not phone calls.