there is no best, there are many different headphones and many different needs for headphones, to which different phones fit differently.
personally i like my semi open akg k141 studio because they have really nicely balanced bass, mid and treble, are comfortable in head and have nice clarity for the price(naturally if you put 150 for akgs, you can get some with bit more clarity). those headphones are more studio type and would be really nice for example mixing(as you need balanced sound for that) or if you want to listen music as it was intended, you hear bass as much as the mixer wanted and when there actually is bass(headphones that are balanced more towards bass tend to overexaggerate bass and you might get some weird "bass" sounds when there actually even isnt any bass intended), same with mid and treble.
but because you didnt mention for example whether you want to listen at home only or you want to listen outside, its hard to say whether some semi open phones would suit you. if you listen outside, you should have closed phones, but personally i prefer ear buds outside over headphones.
majority of people like the sound that sennheiser gives(personally i dont, not even the 500$+ ones), bit darker on the bass and more balanced towards bass with not so natural(sounds more metallic in some weird way) and less balanced mid and highs(not that mids and highs arent there, but instead of ---------- its more like ''-,''-.''), because for some people its not about balanced sound, but sound with much bass.
but yea go look hear-fi and keep in mind that semi open(or open) is not good for outside(as wind might get in and fuck with the sound and more of the sound escapes the headphones to other people from open/semiopen, but that open construct also makes the sound more pleasing and you dont feel the same pressure as you do on closed) and sennheiser, even tho its praised by many, is not very balanced on its sound(but you might like it)