The best solution I have found is to get yourself a small USB stick and install LiberKey on it. Then make sure you install CopyTrans Manager through the LiberKey program manager. Attach the USB stick to your keyring. Now, anywhere you go and you want to put some music on your idevice without having to deal with iTunes, just plug in your USB stick, run CopyTrans from the stick and profit. The music will be added to your device, the library will be properly updated and you can use the stock music player as well.
Of course this is assuming the OP's iPod is a Touch. If it is an older style device I'm not sure what the options are.