DO NOT GET PBR (POKEMON BATTLE REVOLUTION)!!
I have it, it's such a waste. Stadium and Stadium 2 were good, Colisseum was sorta crappy and I never have played XD.
PBR is only good for random wi-fi battles, which most people use all legendaries/Ubers anyway...
There are NO mini-games, it is all stadiums you have to beat and it's pretty worthless.
GET DIAMOND/PEARL and possibly a GBA (Sapphire, Ruby, Emerald*, Fire Red, Leaf Green) game to go with it. I highly suggest *.
*EDIT: @ Digital Mudkip: PBR does not require D/P... You can use rental passes and battle with the game's Pokemon (although not as nice as your own trained ones).