What a great topic. We were just discussing and debating this last week. In my eyes the ideal solution is they way I used to do it before I started using Marketo landing pages, on the TY page, a server side script would push the asset download to the user (a Save/Cancel dialougue box appeared over the page), while also making it available as a link. That's the best of both worlds. The underlying TY page had a 30 second delay on it, then would refresh to a related page on the web site.
For a lot of content, there is an automatic follow up email also containing a link to the asset...just in case.