What is the best Newsletter software/service?

Hello fellow members,

I was wondering... what is the best low cost/free email subscribers software/service out there?

I would like:
* 10k subscribers add possibilities
* Filter lists possible (Languages for example)
* No limit on sending emails each month
* Subscribe-Unsubscribe possibility in the emails
* Lot of graphic choices, like email templates and button adds for social media

Hope someone can help me out with this question.

Kind regards.