I agree "studio monitor" doesn't mean much these days. It does mean a speaker designed to produce sound in a very small room. IMHO look for speakers that have an actual +- 3 db specification of frequency range. Most consumer speakers only mention a frequency range with no +- tolerance quoted. Maybe +- 10 db, may be anything. RadioShack used to have great specs,and lousy sound, but a brochure on their headphone let out the secret. The headphone had a "production tolerance" of +- 20 db, which means if it made any noise at all they shipped it.
In my market the best bargains are Peavey speakers. I bought SP2's which have a quoted +- 3 db range of 54-17000 hz. I auditioned first some SP5's which with 70 hz lower end were not low enough fro piano or organ, IMHO. 54 hz is, and the SP2's are only down 10 db at 44 hz.
these are Woofer + tweeter two way speakers, and require 10' or frontal space so for the stereo image to meld with 6' separation. I have a 14'w x 10' high x 32' long living dining room, with the speakers on one end of the room on poles above and straddling the piano. This projects the sound anywhere in the room 10' away, even the couch to one side, and also through the single door into the kitchen 40 ' away when I eat meals. If your room is irregularly shaped or very small, some other type of multi-element speaker may be more appropriate. The harmonic distortion levels of the SP2 speakers are so low at 1 W, however, that Peavey plots them in their customer brochure. Look for that on any other speaker! I run mine at about 1.5 Vpp average into 8 ohms, < 1 watt. Acoustic suspension speakers will require much more power to produce the same level of sound, as these SP2's are 98 db at 1 m at 1 watt, pretty sensitive. Yamaha and JBL produce similar 2 way speakers in the pro line, and Peavey has some self powered ones with a little looser specifications in the customer brochure.
I find the huge warehouse stores useless for auditioning speakers. I take my own piano CD's out, and try out used speakers at people's houses, that are selling them off. A good piano CD is one of the hardest sounds to do correctly, so they make a good test. I got the SP2-XT pair, speaker stands (poles), a wedge monitor speaker with 15" woofer and horn, an CS800s amp with issues, a 15 band stereo graphic equalizer with issues, a digitech quad 4 effects box with issues, a 100' 20 out 4 in snake cable, a road case, a 12 input mixer with phantom power for condensor mikes (with issues) for $1000. This was from a band leaving the road. the issues are mostly tired electroytic caps in the power supplies or blown $.30 components on the inputs or outputs due to the band plugging the 1/4 phone cable in the wrong hole in the dark when setting up. All this equipment was from 94-95. the speakers have been perfect, other than all the tobacco ash covering them that I beat off the wool before bringing them in.