I was playing on my travel notebook the other day and I was having some issues with winamp so I tried foobar2000. I found this very good compressor for foobar2000 called foo_r128norm.fb2k-component.
If you are a foobar2000 user you may want to check it out. I had very good luck pulling little whispers out of the background with it, yet not getting my ears blasted out by the loud stuff.
The exact DSP compliment I have been using is the built in EQ and the built in advanced peak limiter and the foo_r128norm (1).fb2k-component plug in. The only thing that you need to configure is the EQ, and I generally keep that so 300-3000Hz is flat and the response rolls off beyond that. It is not hi fi, buy most of the intelligence in the human voice is in that range.
If you try it, let me know how it works for you!