Hey Christian-
I have several additional channels beyond the marketo standard. One example is a channel for each type of content we typically produce, White Paper, Case Study, Product Literature, etc. For each piece of content, we produce an "asset specific landing page" campaign, which is then utilized in other materials like newsletters & lead nurturing.
The only time I use "email blast" is when I will only ever use the content a single time for a single purpose. I need to send out an email about something small, without a form/landing page. I use Eblast. For everything else I use the specific content channel, rather than the generic content channel.