A key component to enjoying your time at the gym when you do not have a training partner is to have enjoyable tunes; not just good eye candy. When home from college on breaks at the local gym, I hated the mix of songs they played. They oscillated between two stations: a family friendly softer station and a top 40 station. Being the prime time for crappy boy bands and teeny-bop pop songs, I heard a ton of Britney Spears and NSync. It was horrible. At college the music was better as the students working the gyms brought in CDs full of great mixes. One of the best was the guy who brought in a CD full of Gun n Roses tunes. One of the weirdest was the CD of the B-52s greatest hits. Not really workout music. No.
Out of college, I joined a gym that played digital, streamed songs that sounded like they were the soundtrack for gay German porno flicks. It made the grunting and enthusiasm between guys even funnier to witness. I finally bought a CD player with a belt to hold it in place. It was awesoem to bring tunes and finally not want to puke. One problem was the problem of the CD skipping as I stood up or was perpendicular to the floor. In my current gym setting, I have an mp3 player. My in-laws bought my wife and I matching mp3 players. Whatever set of music I want to listen to is at my fingertips. With an armband and an incredibly lightweight structure, my mp3 player is almost forgettable as I do reps.
As far as stacking that player with tunes, I rotate music but do have a general requirement for my tunes. They have to be fast paced. No ballads, no really long built up songs, no pussin' out. I will give you a list for my favorite stretch of tunes on my 14 song rotation....
DMX - What's my name
Electric Six - Gay bar
Eminem - Lose Yourself
Fall Out Boy - Sugar we're going down
Fort minor - Remember the Name
Fuel - In my hands
Karate Kid song - You're the best
Lo fidelity all stars - Battleflag
When those songs are playing, it's easier to focus on working out. Enjoy your gym.