Which monitor speakers are the most detailed...

My budget is $3K. Thanks.

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.