Good inexpensive headphones ....?

you should check
Samson SR850

under 50 euro
and sound great.
best cheap monitoring headphones.

i also use 2 pairs of more expensive headphones
but - just go to a store and listen these Samson SR850.

all my friends that make music here got a pair after hearing mine :)

as for expensive headphones:
Audio-Technica ATH-M50
Beyerdynamic DT 880
AKG K702 ( and K701)

+1 for Sennheiser

I have pretty cheap “almost hi-fi” Sennheiser HD202.
For sure they colorize the sound a bit but for just listening music the’re pretty good. My ears never got tired from them even after listening to Machine Head, Lamb Of God and Devil Driver all day long :)

So I got a look at some more expensive 'sets, I really like the Beyerdynamic models, but some have 2 editions, a 80 Ohm and 250 Ohm. What’s the effect of this difference? (aside from a few euros, nothing on a 140 eu piece…)
Are they regularly picked for studio/live or something? Because I remember vaguely that one of them had like 3m cable and the other one avg 1.8…

The hd280 pros are extremely popular but sound absolutely awful and are uncomfortable. So I’m going to have to disagree with you there a little.

The OP needs to give way more info about his requirements.

Yes, Beyers are known for being very good (I’m using dt770 pro on daily basis) but as you noticed they arent cheap and the thread is about cheap ones.