i dunno if it would be made as a top 10...but yeah;
obviously if you want two people to play a game, you will need 2 remotes (so 1 extra one)
my advice would be to get wii play, with the remote, its just a few mini games, but they are pretty decent..
depending on the tv you have, you may want to get a set of component cables, as the picture quality is better with these..
either get some rechargeable batteries for the remotes, or there is a new charging dock accesory coming out very soon, keep your eye on that, as you will go through alot of batteries.
if you are wanting your wii online, then you need to either have a wireless router, or get hold of the nintendo wi-fi usb connector (or there is a LAN adapter if you have a ethernet router)
its not a top 10, but its a few things to take into consideration..