Speaker placement..

How far do most of you guys/girls position your loudspeakers from your walls?I know every room and speaker is different but i need help.My room is 24' long and 17.5' wide, know matter where i place my speakers it just doesn't sound right to me.I have acoustic panels and diffusers in my room so slap echo is not a issue.It's mostly trying to intergrade the imaging with the bass.It always sounds flat unless i'm right at the back wall or right on top of the speakers. My speakers are Artemis eos signatures w/large bass modules.the room is for my stereo only so i could place the speakers anywhere.Any help would be great.