After putting a bit more time in with Zelda, I take back what I said. The speaker sucks. It is now muted.
It works well for Wii Sports. And there are certain times in Zelda where, if the speaker volume isn't too loud, and sound is coming out of both the speaker and the tv simultaneously, it creates a nice surround effect....like when it's raining. Oh, and Minda's laugh is nice.
...But then there are times, like when you swing your sword, or cast your fishing line, where you'll look around for the cheap action figure that's making all the annoying noise, only to discover that, apparently, the $300 you paid doesn't quite cover non-crappy sound effects that don't make you want to claw your eardrums out.