Hi , I wanted to ask what the most aggressive variation against the Budapest Gambit is?

Against it...!? Not sure if we are allowed to give out that information . I consider the Alekhine Attack to be the most aggressive...

http://www.chess.com/opening/eco/A52_Budapest_Defense_Alekhine_Variation_Abonyi_Variation

tnx Polleke,

Is someone interested in playing it?

just challenge me :-)

A very aggressive choice is the Alekhine variation.

1. d4 Nf6 2. c4 e5 3. dxe5 Ng4 4. e4

However, playing offensively against a player who is out for a fight doesn't seem like the smartest idea in the world. In this variation, White grabs the center, leaving a lot of holes for the black pieces to manouevre, such as d4, c5 and b4. I never have any problems with that variation with Black. Not to mention that Black can throw some sand in your face with the unusual move 4. ...h5!?

If you want to be a pest with White in this opening, develop solidly, supress any Black counterplay and typical manouevres like the queenside rook lift and you have good chances of getting an advantage eventually. A particularly nasty setup is the Smyslov-Spasski attack.

Looking at my own games, somehow on this site I had most trouble with 4. e3... A quiet manouvering game is what you get, not really what you want as black I guess. 

Yeah, polleke's suggestion also has merit. 4. e3 is all the rage now. It's not the most aggressive move, but it is extremely solid.