Re: What is the best way to set up a resource center?
As I'm sure everyone will be quick to tell you, there are lots of ways to go about this.
I believe a traditional gated method is a combination of both, working something like this:
A "resources" kind of page on your website, listing all of the resources and categorizing them appropriately. Each of these is a link to a Marketo landing page with copy and images specific to the resource, with a form. Form submission goes to a thank-you page, and either that thank-you page has a link directly to the resource or the resource is emailed through Marketo to the person.
If you have lots and lots of resources, you might look into a content marketing platform (e.g., Kapost). If you don't, you can just store the PDFs in Marketo, and reveal the links appropriately.
Then on your website, you can use your CMS of choice to add a new short excerpt and image to the new resource landing pages as you create them.
Does that answer your question? I don't know if you were looking for a more specific answer or not.