I'm not going to pretend that I know anything about "art folios," but I guess I'll be getting one with Metroid: Other M.
You see, I've already reserved the game at GameStop. And by doing so, it guarantees I'll be receiving a "collectible art folio featuring 16 individual high-quality cards." Not sure how big this thing is, as the picture on GameStop.com could be misleading; I can't tell if they're the size of business cards or legal paper. Who cares; my guess is they'll feature some stunningly awesome Metroid artwork, and that's good enough for me.
Metroid: Other M was supposed to be out pretty soon (on June 27, in fact), but has since been delayed until August 31. I've already played it, so check out my hands-on impressions and details from the preview I ran earlier this year.
Metroid: Other M [GameStop via GoNintendo]