I love the WSC. I don't use it very often though, because I'm broke due to my reluctance to do chores. Anyway, I think I like the WSC most for two reasons.
1) The Virtual Console offers to me the chance to play retro games that I didn't grow up with. Thanks to Cinemassacre and ScrewAttack.com, I know about the old games and thanks to the VC Service, I can play classics like Gunstar Heroes, Ristar, Super Mario Bros 3, Super Metroid, and Street Fighter II: Champion Edition. Only two problems: most of the Rare games aren't on it and Earthbound isn't on it.
2) The WiiWare offers the chance to newcoming video game companies to get a headstart. They pump out greatness. 2D Boy did awesome with World of Goo, and the job done on SBCG4AP was phenomenal. I heard the Oregon Trail is on WiiWare, but I can't seem to find it. Is it a lie? Anywho, Konami is performing epically with the rebirth series on WiiWare. (I can't put Gradius down)
Oh and before you make your first decision, don't buy an NES title on VC unless you are very skilled at video games and/or aren't frustrated easily. Believe me, Metroid, Kid Icarus, and Super C taught me not to choose a game just because of a recommendation.