Fine Volume Control 2.0 gives the ability to change volume in 1% increments and adds an optional replacement for the standard on-screen volume dialog which includes a dial to help adjust the volume when not in-app.
If you can never find the perfect volume level or you want to go below 1 bar of volume, then this app is a must-have.
• 100 volume stages instead of 15 (excludes in-call volume)
• System volume dialog replacement – change volume with the dial when not in the app
• Option to disable overlay when in certain apps (e.g. games or alarm clock)
• 5 dial colours and dialog visual styles
• Fully customisable dial size and sensitivity
Download the trial here: https://market.android.com/details?id=opotech.finevolumev2
Buy the full version here: https://market.android.com/details?id=opotech.finevolume.unlocker