Theoretically you should match the sample rate to that of the original recording to avoid resampling, which means 44.1KHz for Audio CD's and 48KHz for most games. As for the bit depth set it at 24 and leave it there, all this will do with 16 bit audio is add 8 empty bits to the signal as far as I'm aware which makes no difference to the reconverted analog signal. Set your windows volume to 100 though, if I recall right the way windows works with audio in the digital domain it basically chops off bits from the audio to reduce volume, some software can get around this by using 32 - 64 bit for the volume calculations for volume but usually just leave it at max. It should also feed a much healthier analog signal to your amp so long as your DAC is decent.
also intersting articel :
http://xiph.org/~xiphmont/demo/neil-young.html
also intersting articel :
http://xiph.org/~xiphmont/demo/neil-young.html
