Having read your description of your room, I suggest that nearfield monitors might be apractical solution for you.
Try to audition ATC SCM20-2 or 20ASL pro along with all the other good speakers people have suggested ... they are in your price range (especially second hand) and an active speaker will save you buying an amp (so add that to your budget).
The actives can get more bass than the passives as the 20's do not go very low. They have excellent timbre, awesome mid range, good but not exceptional imaging with a large sweetspot and play accurately at low and high sound levels. Good luck!
Try to audition ATC SCM20-2 or 20ASL pro along with all the other good speakers people have suggested ... they are in your price range (especially second hand) and an active speaker will save you buying an amp (so add that to your budget).
The actives can get more bass than the passives as the 20's do not go very low. They have excellent timbre, awesome mid range, good but not exceptional imaging with a large sweetspot and play accurately at low and high sound levels. Good luck!