Lots of detail, great imaging, not much bass?

Tekton should be on your list to consider.

06-02-13: Nonoise
I just got back from the Newport Audio show and if you can stretch your budget another $100, there was the Martin Logan Motion 15 that made more than adequate bass and sounded pretty good for a monitor. Actually more than pretty good. ...

The sound attracted my from out in the hall and at first I thought it was their electrostatic panel speaker with the built in sub playing.

The Martin Logan Motion series uses the same type of folded ribbon tweeter as the GoldenEar products. This is a very extended and natural sounding HF transducer, and works well in both products. Emotiva also uses them in their powered monitor Pro series, but since you have a Classe amp, I didn't mention them. Point being that this 21st century realization of the Heil air motion transformer is gaining some traction in speaker design.

Amphion Helium might be good in that situation also.

Headphones, my man. fuhgeddaboudit!

I've been through quite a few models of bookshelf speakers over the past few years. I've had a couple of NHT models, a couple of PSB's the Epos Epic 1 and for the past few months, I'd kind of settled with 3 speakers that I was rotating in and out of the system, the Harbeth P3, the Kef LS50 and the little Silverline Minuets.

The Minuets are fun speakers. With the right music, they really can do some magic, but you have to be aware that they can fall apart fast with the wrong material. When I have them running, it's not uncommon for me to put something on, smile, shake my head and just think...nope, they are just not going to pull that off. Remember, this is a little 3.25 inch driver in a very small cabinet. However, with most stuff and within volume limitations, they can produce some wonderful sounds with a nice little sound stage and tight imaging and that is what has driven me to keep them despite also having the Kefs and Harbeths.

Just this past week, I've had a new speaker come in that is starting to give me everything the Minuet does but on a larger scale. It's a single driver Omega Super 3XRS. The speaker is still breaking in, but it's really starting to sing and I'm starting to think that this may be the one that brings me to selling all the other speakers. It's that good.

Being a single driver design, it does run out of steam earlier than the Harbeths or Kefs, but can handle bigger and louder music than the little Silverlines and would be a great speaker for those not looking to bother their neighbors. The detail and imaging of them is the best I've ever heard in my room by a good margin. If you have a way to hear them locally, I think they'd be worth a listen as they do make models in your price range.

That said, one thing I've learned is that the state of small speakers these days is so good, it's not hard to find something that sounds good, in fact, it'd probably be harder to find something that sounds bad as long as you go with one of the well recommended models.