After 4...Nf6, the game has transposed to the Modern variation of the Two Knights Defence (usually 1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.d4 exd4).
After 5.e5 d5, I think the normal continuation is something like 6.Bb5 Ne4 7.Nxd4.
Google for "two knights modern" for more information, e.g. http://correspondencechess.com/campbell/hard/h990927.htm
whats the best line for aggressive, attacking players that likes open games?
From a whites point of view.