Which monitor speakers are the most detailed...

Detail and musicality is a balancing act, as Tacs says. Harbeth HLP 3ES, or 7ES, have both in spades. Great speakers. Good luck!

I assume by Monitor you mean a non floor standing speaker.

Take a look at Northcreek.com. They have a simple kit called the OkaraII. Buy the innards for $629 and have cabinet made by Lee Taylor. Scan Speak 9500 tweeter and Vifa woofer, Cresendo Caps in the crossover. You will have $1500 in it by the time you are done and, IMHO, nothing in your price range will touch it. Not brain surgery to put it together -- a good experience.

Both Harbeths mentioned above are great. The Compact 7 has the the unusual midrange clarity/detail the result of the material used to make the 8 inch mid-woofer. Smaller than the Harbeth Compact 7, but bigger than a mini-monitor and still using the same mid-woofer, and still in your under $3000 price range, is the Harbeth Monitor 30, the primary mid-field monitor used now by the BBC. (The much larger Monitor 40 is the large reference speaker used by the BBC and the Monitor 20 - which is the same speaker as the HLP3ES - is their near field monitor. I doubt there are any Monitor 30's available in the US, but you could contact the distributor.

I second the Taylo Reference monitors. About $1400-1500 used with stands on A'gon or from Tyler Acoustics directly.

In my opinion for $1000 the AV Reality Avinci Ones "take the cake". (Go to their website to read my glowing review). The best part about AV Reality is their price. For what they cost, they cannot be beat. Truly a state of the art designs with top of the line drivers.

Something else to note: AV Reality is making an even better speaker called the Avinci "Studio", which is a knock off of the $9500 Krell Lat monitor, for $2000! From a driver and crossover implementation perspective, the AV Reality Studio ABSOLUTELY crushes the ACI, Merlin, Totem and Dynaudio speakers that you mentioned.

In comparison to any other speaker manufacturer that I know of, AV Reality's Avinci speaker line offers audiophiles an unprecedented value in ultra high end speakers, using only the best drivers and crossovers. Have I said enough?