Harbeth HL5s. Instantly hooked when I heard them. Kicked the snot out of the DeVores and Zus I heard.
Harbeth sais that they want a 25wpc+ to sound their best, but the 300XS has no issues powering them (and even has a proper 6ohm setting for them). I don't doubt the 600 is even better though (at over double the power).
My dealer said that out of all the stuff he sold if he had to close shop and be done he'd keep HL5s and the Leben 600. That's a pretty bold statement.