New Speakers To Buy

SalkSongTower from Salksound.com.

"Without knowing your budget I would recommend a used pair of Proac Response 2.5. A lot of performance for a little less than $2,000."

True, but I see 2 problems with that speaker. They don't meet the sonic description that the OP is asking for, and getting the bass right in a fairly small room that is almost a perfect cube, would be a nightmare. If the OP came across a pair of Future 1's or .5's, that would be a different matter. But they're hard to find and may be out of his price range.

Ref 3A

depending on your musical taste I would recommend Totem column speaker line from the Arro to Hawk. And/or JM Lab electra series because it is a huge step up from the Cobalt series. If your not a hip hop or rap fan and listen to things at normal levels, these should work. If you not, just get the tweeter or go to the electra's.

fritzspeakers.com

Harbeth P3ESR !

In any case you decide, your tweeter is replacable and no brainer to replace if you really liked your current ones. Will probably cost you the smallest and smartest investment considering the fact of some hassle to order and to set-up new speakers.

I would take your JM Labs over any of the newer speakers you list.

"Looking for a wide and deep sound stage with a depth of detail from that speaker."

If that's your goal, my first choice would be a pair of Vandersteen 2's, but I think your room may be too small for them. A small pair of Audio Physic or Thiel should work very well for you. Or, if you like your current speakers, maybe stay with that brand.

Without knowing your budget I would recommend a used pair of Proac Response 2.5. A lot of performance for a little less than $2,000.

Ref 3A