^^ You should get at least one extra controller and one extra nunchuck. The Wii comes with "Wii Sports" which makes use of those things.
"Wii Play" is a game that comes WITH an extra controller (it is actually just $10 more than a controller on its own) so that's worth it to get.
Other accessories that you should get are a NYKO (brand) charger stand, which comes with rechargeable batteries, since the Wii remotes eat up batteries. Also, if you have a component video-in on your television (i.e. your "video-in" input has red-blue-green plugs instead of just one yellow plug) then you'll want to get a component video cable for the Wii, which allows it to display in higher resolution.
http://monoprice.com/products/produc...seq=1&format=2
^^ get your component video cable from that site, since it costs like $6 instead of $30 retail.
Games to get:
Super Mario Galaxy is a must-buy.
Legend of Zelda: Twilight Princess is a lot of fun (single player).
Rayman's Raving Rabbids (1 or 2) would be fun to get for "party games", as would Mario Party 8.
Super Paper Mario is fun too!