Even if it is expensive, I would go for the official component cable because from my own experience, they are almost guranteed to work perfectly, and not just for the Wii, but for other consoles as well.
I had 3rd party component cables for my PS2 and Wii connected to my 52" Sony Bravia LCD TV and the image came out all fuzzy and pixelated. Even trying to sort out video display settings on both the TV and consoles respectively did nothing to help. Switched to official cables for the both of them and the images have been perfect since.
For another test to see if the 3rd party cables were duff, I tried connecting the consoles and component cables to a different TV and found that the picture image was perfectly fine on there i.e. 32" Hitachi LCD TV. I thought it was weird, but then I figure it was to do with a lot of things that may affect it, the quality of the cable, the connection ports, or the TV itself. Official cables worked perfectly fine as usual.
So yeah in conclusion, 3rd party cables can be a hit or miss. They can either be crap, or they can work just as good or better than official cables. It's just dependant on luck or any other factors to it.
