I have a pretty good ear (musician for about 10 years) so I am constantly tweaking my settings on a song by song basis. I did do an initial tune though.
If any of your friends are good with stereos, watch what they do. In the end, I chose the highest quality music I had (meaning 192kbs or higher on MP3) and of the most common music I listen to. For my choice I chose:
Tommy Lee - Good Times
Ryan Cabrera - Shine On
Police - SOS (Sand Ver Doom Mix) ...house music mix
Laugh all you want but those three have a nice range of acoustics. If you have any Sade, U2, or Elton John, I would use those too as they have excellent recording qualities and great detail acoustically as well.
I brought my car to a parking lot and kept my windows closed. I then played each song at 75% volume and went to town. You have to see what fits you best. I usually tune the sub first, then go up in the hZ rating.
Any questions, just ask...Hope I can help.
edit: RW: Funny we both touched on similar things

. I have my subs filter at 80hz and high-pass at 125-hz too... :LOLOL