There were some high hopes for Nintendo's Wii round these parts: thoughts that it would broaden videogames' appeal, make interaction more intuitive, that the Virtual Console would make the generational aspect of videogame hardware less restrictive—but it's never really lived up to that. There have been lots of hardware sales, but not the diverse software range we usually see in similarly do-welling systems (NES, PlayStation). There are some interesting games, though!, as well as Gamecube backwards compatibility, and digital releases on WiiWare and Virtual Console. It's also really easy to get homebrew stuff running on it, so it's easy to play imports, and makes a great emulation box.
Starting in 2015, Nintendo has begun releasing select Wii titles as eShop digital downloads on the Wii U. That console is already backwards compatible with Wii games anyway, but the digital lineup thus far seems to give special attention to games that received limited print runs or are currently hard to find, so you might want to wait up before spending a lot of money on rare Wii games.