What would be a fundamental wordpress plugin stack for Internet Marketing?

[Mastermamo]

I ask for recommendations for wordpress plugins for the fundamental functions needed for internet marketing sites.

I know each site has a purpose, so for each I ask for plugin recommendations either free options and/or the premium options. I already bought several things that I've used before like Optimizepress and other plugins and themes, but I haven't programmed sites in 2 years so I want to get up to date for other plugins for security, ecommerce, autoresponders, social posting, etc.

Thanks for your reccomendations. :)