have you noticed that some of the more detailed games like animal crossing or the rune factory games, limit the wifi capabilities to friend code only, thats always seems to run the wifi capabilities threw the mud
(im not voteing for them but the rune factory games arnt on the list)
ill vote for
phantasy star online (it runs multiplayer with random people, but you cant freely talk to them...)
diddy kong racing (on of the better online racing games with random people)
zelda phantom hourglass (good capture the flag game)
*spectrobes: beyond the portal (the disny chatroom in this is acctually pretty cool)
pokemon dimond/pearl/plat. (one of the best randomized world wide trading systems)
Jump Ultimate Stars (a good world wide fighting game, too bad japan likes to keep japanes games in there own languages)
* = the onlyone i didnt see on the list