Current top player with most aggressive style? Which current top player (at least ELO 2600) is the most aggressive and most
 compromiseless player (of course only on the chess board :) ) ?

Beliavsky is a candidate for this topic, but I do not know, if he still has this
 style.
Baadur Jobava is probably the most aggressive top player right now. If you go even further up the ranking, Mamedyarov is very aggressive as well. 

And although he is not one for wild and dubious attacks, Caruana is actually quite uncompromising, his draw rate is very low.

Topalov and Morozevich are two names that stand for aggressive chess. But I think they both slowed down in recent years. The same could be said for Nakamura.