@Entroper: Well yeah, that's another thing to consider for Wii ports and that many people seem to forget. A game like Portal doesn't has super-high res textures, even on the final levels AND even when set on high. So at medium+480p wouldn't make much of a difference. (Kinda off topic: I know you are a programmer... have you worked on the Wii yet? Any word on the GPU architecture?)
Also check this comparison screenshots for the settings on HL2.
Model detail:
http://www.tweakguides.com/images/HL2_7a.jpg vs http://www.tweakguides.com/images/HL2_7c.jpg
Shader detail:
http://www.tweakguides.com/images/HL2_8a.jpg vs http://www.tweakguides.com/images/HL2_8b.jpg
Texture detail:
http://www.tweakguides.com/images/HL2_Textures.gif (1MB .gif file) (I'm the only one that thinks that @low the texture look like SMG's? Heh)
HDR:
http://www.tweakguides.com/images/HL2_10a.jpg vs http://www.tweakguides.com/images/HL2_10b.jpg vs http://www.tweakguides.com/images/HL2_10c.jpg
As you can see, the Source engine is a very scalable one.
