Speaking of the Gamecube, just thinking of all those classic GC games we could get on VC... Playing them as a handheld will be so... unworldy. A proper new experience.
Games like: The Capcom 5 (PN03 my personal fav), REmake (I-fucking-magine playing under the covers at night!!), Pokemon Colisseum & XD (weakish sauce but still a new experience), Twin Snakes, even obscure games like Final Fantasy Crystal Chronicles could feel more inviting, especially if they gave it an online mode.