Need a car-friendly way to listen to music? 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.
Go download PowerAmp.  Best $5 I ever spent on an app.

It includes lockscreen controls and I'm pretty sure you can set up lockscreen gestures to do whatever you want.  I'll confirm this real quick on my installation.

Edit: Confirmed on the lockscreen gestures.  Swiping left and right over the album art will skip the track forward and backward by default, from anywhere in the app or on the lockscreen.