Here is specifically what I'm looking for.
1) I would like the ability to use gesture/swipe controls to skip tracks. This is much easier than finding a button on a touchscreen to change tracks.
2) Ability to either prevent a lockscreen or control the player from the lockscreen. I don't mind if I have to push the power button to get the screen to wakeup, but once I do, I would like the ability to control the music player without going through the Android screen lock. I see this accomplished through either a certain type of music app, or some application that allows me to control what applications prevent a screen from locking.
I have a rooted Samsung Captivate (Galaxy-S) running a custom ROM variant of 2.2.1.