Compared to the Droid, the Inc has better depth, clarity and a little more volume. My N900 kicks both their butts, since it has a built in audio amp for the 3.5mm jack
If the phones you are using have above 16ohm impedance, you could have a lack of volume and resulting loss of gain (hence less sound quality), since the volume is not loud enough to push high impedance buds.
The Vmoda metals work great and are 16ohms. Also of all places, Walmart sells some Altec Lansing buds made out of wood, for $25. They have the best sound I have heard in buds for under $100. I kid not
They work well with the Incredible
I prefer those to my UE's and Vmoda's. Better depth and clarity than those buds. It could be my imagination, but sounds good to me
added:
I am not kidding about the Wally world buds. They are amazing for the price.