I know what you mean. I can easily tell the difference between 128k MP3s and the original, but once you get beyond 192k, the differences are so minute that it's not worth the hassle. Personally, I just use V0 MP3 for everything as to me, it's the best compromise between quality and file size, and I really cannot tell the difference there at all - even through my hifi. And it means that I get to run all my music through MP3Gain to level the volume in a way that both Winamp, iTunes and my iPod all support.
As for FLAC and whatnot, I don't see the point of it really. Not when you see just how much they destroy modern music during mastering anyway. Does clipping really sound better when it's lossless for instance?
EDITED: 28 Oct 2011 11:53 by DAVE!!