I wish I had never purchased Mario Party 8. No widescreen support, and the game seems to run much slower than even 30 fps. I immediately took a hit and returned it to Blockbuster - if you really want a Mario Party game, I would recommend either #5 or #6 - both of these Gamecube games are great and they run much better.
If you're going to build a computer that would be powerful enough to emulate a Wii (and that's assuming you have a good emulator) you might as well spend a small percentage of that money and buy a real wii, mod it, and get some games. You get the real thing, and for a lot less money and more stability.