Your wife seems to be like my girlfriend. I got her a Wii (and me too, but if it wasn't for her, I doubt I'd own one), and she loves the damn thing.
Her favourite games on it have been Super Paper Mario and Super Mario Galaxy. Get those two games and you're set for a few months!
Price wise, that's as cheap as it's going to get for a Wii. Snap it up now while they're stock. The closer it gets to Christmas the lower supplies will get.