Well for one thing it's only $200 now which, at least to me, nearly borders on the verge of impulse buy.
Also, despite some dry periods here and there, overall it has built up a strong library of games over the years: Zelda TP, NSMB Wii, Metroid Prime Trilogy, Mario Galaxy, SSBB, Mario Kart Wii, Little King's Story, Zack and Wiki, House of the Dead: Overkill, RE4, Strikers, etc. Plus you got all the Wiiware and classic VC awesomeness. Some of these games, mainly the 1st party ones are still full price or close to it, but many of the good 3rd party games I listed are going for pretty cheap nowadays, some even at low as $15-$20.
And it looks to only get better in the near future with stuff like Monster Hunter 3, Fragile, Galaxy 2, Sin and Punishment 2, Xenoblade, Epic Mickey, and Tales of Graces coming.
Essay Pro