The Dangers of Clipping

Wow, old thread.

@blackbird: I agree about the lows. Usually during tom-centric parts, you'll find the bass on the toms and bass guitar itself will build up until you can hear some crackling. I really hate it when that happens. Usually when things get really dense in the mix, there's a greater chance of audible distortion.

@Morgoe: I don't use Gclip, myself. I use the Timeworks Mastering Compressor, and try to apply it as sparingly as I possibly can. I tend to use it until the green reduction marker is just barely registering. I just try to clip the drum transients to get a little bit extra punch out of the mix that you'd lose by just hitting it with a straight limiter. Much of the time I'll simply listen rather than look at the gain reduction meters and ask myself whether there's enough punch, audible crackling etc. In the early days I recall taking off quite a few dB with the clipper, but I try to be much much more sparing now.

As Steven said earlier in this thread, a large part of all of this is having a spectrally (is that even a word? I keep using it and it makes me sound smart, so I'll keep going...) and dynamically controlled mix. You'll find the better the mix, the easier it tends to be to get level out of it in the end, and the safer it tends to be to clip (if you're so inclined).
 
That were some useful informations Moonlapse, but if you want to do mastering on your own, buy yourself Bob Katz's "Mastering Audio - the art and the science" book. There is great lot of knowledge that everyone should have.
Talking about mp3, when you compress your files to mp3 the RMS level goes up, so when typical recording is premastered for mp3 it hits -1dBs and no -.3 as usually.