Death or speed metal in anything other than FLAC or 256+kbps MP3s is unlistenable (more so than usual). The hihat hits become a wash and the cymbals sound like shit. 128kbps is fine for classical or pop.
When I'm in my car I listen to mp3s with "mp3 boost" compression and normalization, as I don't like adjusting the volume (try listening to Epitaph by King Crimson in the car, there is too much dynamic range). When I'm sitting in front of my computer I listen to mp3s or FLAC hooked up to an e-mu 0404 and alesis mk2 monitors. So all together my sound system costs ~$500, I have a good signal path, good digital converters and have no need for "audiophile gear". And yes I've done ABA sound comparisons and I can tell the difference, but then again I can hear CRT monitors and the "mosquito noise" sounds.
I want to get a record player soon, not because it has magical properties over digital, but because records are often mastered for their audience and not compressed to unbearable levels like current CDs.