I ride MUP for 90% of my route, got a 30gb Ipod for Xmas, it's about half full. I have it on random right now, but I'm going to set up some playlists. The louder and heavier the better. It's always great when Motorhead happens to start right at the bottom of a steep hill.

Exactly why I say have one ear free to hear other people. I hate that too wit joggers/walkers where you can can hear thier music while you're slowly approaching them. I ring once, they don't hear, as I get closer and ring again some hear and some don't then they get all panicked that a bike just passed them without warning and start yelling at you for not giving them warning. Sometimes some people don't even hear the second ring as you're closer and you have ring and yell at them then they take notice of you.

I also hate the people on bikes with the music so laugh just like some joggers/walkers that you can't move around them as they're as manueverable as you are and you can't predict thier movement till you alert them. I've tried passing one rider beore with the audio so loud I could hear it before I even got close to them and they just freaked out and almost took me out into the water bank as I was passing them.

Also having both ears plugged especially for ladies on foot just cuts down thier awareness to what's around them and you while feel sorry for them if they are attacked but in a way you kind of can see that attack just sooner or later happening as they can't hear others behind them.

I avoid listening to music or anything other than my environment as much as I can . I will admit to listening to a Sunday afternoon hockey game recently on a rail trail ride with my girlfriend, but even then I had the earbuds dangling below my ears suspended by the helmet straps. I won't even consider using them on the road.
Even when I'm in a "safe" environment like a rail trail I still don't actually put the bud in my ear. I do it like this.

The bud (green) ends up right below my earlobe allowing me to hear the radio, but doesn't impede my hearing. I by no means advocate this for traffic, but in a "safe" setting it works for me.

somewhat on topic... has anyone tried bone conduction speakers?

i would love to try some but don't see them readily available anywhere and am not inclined to purchase without playing first.

then more on topic...
i listen to both in-ear plugs and am more likely to ride when i have the freedom to so. if it is a more dangerous ride then it is nothing noticeable to me, i almost always see an approaching cyclist in my mirror and i have never have had anyone make a negative comment towards me regarding the headphones.

my favorite tracks for cycling would be highly energetic.

i dig metal..
Strapping Young Lad- Detox
Gojira- Backbone
In Flames- Take This Life
Death By Stereo- The Plague
Opeth- Bleak

also am into real punk.. not the Dookie bubblegum crap...
Nofx- Don't Call Me White
Gogol Bordello- I Would Never Want to Be Young
Rancid- Olympia, Wa
Suicidal Tendencies- Possessed

and if i had to admit it, i like good country... no Shania/Toby crap
Steve Earle- Tanneytown
Drive By Truckers- Gravity's gone
Uncle Tupelo- Chickamauga
I Can Lick Any Son of a ***** in the House- 665

then for the standard Radio Rock type stuff...
Tool- Rosetta Stone
System of a Down- IEAIAIO
Deftones- Knife Party
Chevelle- Another Know It All

Rap...
NWA- Straight Outta Compton
Public Enemy- Don't Beleive the Hype
House of Pain- Top O'The Morning To Ya
DMX- RuffRyders Anthem
Beastie Boys- Pass the Mic

Audiobook Favorites...
Stephen King- Wizard and Glass
Jeffery Deaver- Garden of Beasts
Jeff Lindsay- Dearly Devoted Dexter
Walter Mosley- The Man in My Basement

Listening while i ride gives me plenty of time to hear new stuff whereas if i didn't listen i would have little to no time to enjoy new music.

Anyones audio setup waterproof or water resistant? Any shortouts?

I've worn my Cowan iAudio G3 exposed in a driving rainstorm with headphones while commuting to and from work and had no problems at all. I highly recommend it if you can find it anymore. https://www.amazon.com/Cowon-iAudio-P.../dp/B00080QYRK

I wear headphones. It cuts out wind noise, but I keep the volume low enough that I can hear traffic.