i think i can give you a gooood advice on this
there are also forums about audio stuff for audiophiles, best forum for headphones
btw, there are earbuds and in-ear-monitors(IEM)
difference is earbuds are open and IEM's are closed
earbuds are mainly cheap and using dynamic drivers (i.e. sony,sennheiser)
IEM's are sound monitors which are used by musicians,singers in studios with custom cases (they are 1000$+)
but you can find similar quality IEM's with universal cases for about 100-500$
spend some time if you are interested, but i must tell you, just like watches, there is no best, sound is subjective and it all depends on what sound signature you like
i got a shure 530, most advanced IEM of shure with 3 armature drivers (1xmid,high 2x low/bass), paid 500€ retail price 2yrs ago here but it can be had for much cheaper from internet, especially in usa
i have tried many most expensive IEM's of almost every brand (UltimateEARS TripleFI 10pro, Westone 3 etc.)
but ended up selling them
from experience i can say for shure530:
it has lush sound signature (warm but not dark), best midrange ever heard, slightly recessed highs and clean,big,punchy bass
wide detailed soundstage
if you never heard an IEM before you will be for sure blown away instantly anyway
this is the EQ settings i use, best sound ever for me