Me? bachelor??? What gave that away??

Thanks for all the suggestions so far. As for my neighbors, well, usually I play the e-kit, and bang on the acoustic during my lunch break when everyone's away hopefully. Either they're very forgiving or scared of me

I thought that perhaps the drums may help act as diffusors, but I guess they have the opposite effect.
I've got an old mattress against the rear wall, but I'll take your suggestion and add some real traps there. I was afraid of overdoing it and killing the sound, but it seems like I've got a ways to go before that happens.
On the left side is a coffee table I've laid on it's side and stuffed two couch cushions on top to act as a makeshift absorber.
So basically, here's what I should be doing:
Speaker stands (think I'm going to go with floorstanders)
Additional absorbtion behind the couch (already have a mattress there)
absorbtion around the drumsets (would some plants in front of the drums work? I think it may be strange, even for me to have some traps there)
trap to replace the coffee table on it's side
