Oh boy, be prepared to get a cornucopia of suggestions. You have a very good amp, but not gobs of power, so you probably want to avoid the power hungry models like Maggies or Inifinity, etc.
There are some good threads that cover some of the AK favorites, so you may want to review those. Most often, it is limited to what you can find locally, your budget, etc. Some brands that seem to get overall good AK reviews are ADS, DCM TimeWindows, OHM, but there are many others. A floor standing model that flies under the radar, but is somewhat hard to find is the original Cambridge Soundworks Tower I (not the II or III). I have a set of Pioneer TZ-9 that is outstanding. The last two are arguably not "vintage", but are good choices nonetheless.