I've been owing Dell for quite some time now, and on Dell machine you need it for the wi-fi and graphics cards (if they have a nvidia, for instance). Don't know much about thinkpads, sorry. But, people lots of people from /g/ use it, and they usually use Gentoo, meaning they compile it from source (almost).

You can use the free version of Debian and install what you need later. But as I was saying, if you're installing on a laptop with no ethernet cable, non-free is the way to go.