Looking for something more aggressive...

[advan]

Any species of Poecilotheria

I disagree.

 

[Kazaam]

I vote for OBT.

 

[Thomas2015]

I might be in the minority on this, but I've had many tarantulas before and hands down, the most aggressive was my P. Irminia. She was a threat displaying, teleporting, tongs grabbing, cricket munching terror on eight legs. Still my favorite out of all of them though!

 

[goodoldneon]

Mountain lion.

 

[Pennywise]

My vote goes to T. Blondi also. Horrible hairs, big fangs and stridulation and maybe 10" +
if you feed them well. All the ones I have had have been fairly active too.