I am asking this for my good friend since i have account here.

He is buying new headphones for his iPod and he doesnt know what would be best option. He wont be buying amp so headphones must work good without amp.

What is important is good soundstage, midrange and warm sounding phones...

He listen mostly to "old" music like jazz (60,70´s), piano music, orchestral... Mostly acoustic music.

He is looking at:
Sennheiser HD595, AKG K240 MK2, K242...

I think that HD595 are good enough for this. What do you guys think what is best? Sennheiser, AKG?

Audio technica seem to work good unamped, unfortunately i have not heard them.
ATH-AD700/AD900 depending on the budget?

Oh definitly HD595. They're warm, beautiful sounding ahve nice bass and are easy to amp.
Although you have to consider, that they're open and have no isolation from noise at all.
Maybe more of a home use headphone, but if he's searching this, I'd say go for it.
Greetz Ava

I am more on HD595 side. How does AKGs compare to HD595? Audio Technica? Never heard any headphone from Audio Technica.