Looking for an aggressive opening for black vs 1. d4 I like the King's Gambit a lot, and even the Latvian Gambit as black (with dubious results), so my style is very aggressive openings with potentially sharp lines and hack n' slash type of tactical sacrifice lines. However as black when facing the 1.d4 opening from white I'm unsure what to do, and just try to play some kind of King's Indian Defence, which seems solid, but I almost never get my pieces lined up as nicely as Kingscrusher does.

So what are some good offensive lines to play against 1. d4?
You seem to enjoy tactical play, so there are a few options for you against 1. d4. As it appears you prefer gambits over other openings, consider looking at the relatively offbeat Budapest Gambit which is characterized by the opening moves 1. d4 Nf6 2. c4 e5 where after 3. dxe5 black can reply with either 3...Ne4 or 3...Ng4 with the latter being more popular. That being said, the Budapest is rooted in strategic themes, and the King's Indian Defense is certainly regarded as the one of the most aggressive replies to 1. d4. 

For a more mainstream approach, I would recommend the Grunfeld as a great hypermodern choice. It's highly regarded from the amateur to world class levels. The general idea is to allow white to build up a center and then target it as a weakness, and the positional themes that arise in the middlegame focus primarily on undermining the pawns on e4 and d4.

For a more comprehensive response, please reference this excellent answer to a generalization of your question.