Added some new headphones, so here is my list updated.
Koss ProAA. The oldest I have and at the bottom of the list, uncomfortable, very narrow soundstage, rolled off and polite bass. Also way to heavy.
Stax SR-X 3 mk III. Second oldest pair I own. Sound is very dependent on the amp driving them. They have a channel inbalance that is very common in electret headphones. Not much in the way of low end impact.
The next ones all have good sound and not necessarily in order of which one is best
Apple ear pods. Nice semi in ear, it allows outside sounds leak in, which is nice for when I am walking or need to be aware of outside noise. Deep bass and clear highs, while it does not compete with top shelf IEMs it still offers great bang for the buck.
Koss UR20. This one runs circles around the Koss ProAA, deeper bass, more sparkle in the highs better impact. Soundstage while wider than the ProAA it still is narrow. Not the best to be had, but a nice cheap pair of heard phones that are not hyped up in the bass or treble like many cheap phones can be. Maybe a contender for best budget headphones
Cyberdrive Impacr Bass. Like they named it, it has a tilted bass response, which with many DAPs can be helpful, not the greatest iem, but worth the price of admission
Auvio iem. I got these on a radio shack clearance sale about 8 years ago. Balanced armature driver that excels in low level detail extraction, the seal and tips can influence the highs. The bass is full, but not as loud as the Cyberdrive iem's decent dynamics, nice over all iem to turn up the music and turn off the outside noise.
Koss KSC75 with Parts Express headband. The killer in budget headphones. While the ear clips work, I find them a bit annoying so I like using them with the Parts Express headband. Bass is a little clearer than the PortaPro's, but not as deep or impactful as them. Nice clear highs that can extract detail good, a very balanced overachiever.
Koss PortaPro The classic! You have all have read the reviews. Still love these little fellows
Here is my favorite and best sounding headphones:
Koss ESP-950. The king! Nice warm sound, not bright not bass heavy, but smooth across the range. These are the headphones that let me figure out what song was playing at the very end of Pink Floyds Dark Side of the Moon, as the final heartbeats are fading out you can hear an instrumental version of Ticket to Ride (think 101 strings version) on the MFSL gold cd. Soundstage champs with a very wide stage, and some good depth to it as well. Behaves nice with foobar2000 using the bass exciter dsp add on. Very comfortable to wear, and very light on the head, also the clamping force is just right. Can be portable in a pinch.
I am exploring Planar headphones for my next pair. Looking at the Monoprice M560 or M1060, I also would like to try the Audeze isine 10 iem planars.
