Knock on wood.
Fortunately, I have yet to experience any power supply unit issues with my Quad G5, but I’m keeping my eye out on the issue in case I’m knocked out of my seat by the loud POP that people are experiencing. I know a few other people that have Quads, but none of them have had this happen to them yet thankfully.
Whenever a new Mac comes out, especially one as nice and powerful as the new MacPros, I get Mac envy. It didn’t seem so long ago that I bought my Quad G5, and now there’s something better, faster, and cheaper! Such is life in the technology world!
tow.com 
Wow, that doesn’t sound fun. I’ve got a Quad G5 too, from right around the time you and Alex both got them, but I haven’t heard anything as scary as that.