The best speaker for a small room...at any price point.

Ilumnia Vocalis

I have Focal Aria 926 speakers in a small room and they sound wonderful driven by two Schiit Vidar Monoblocks and a Mytek Brooklyn DAC+ / PreAmp.  They will not overwhelm a small space but retain excellent detail, transparency, and fast response while remaining very neutral and not bass heavy (I find key for something like a small guest bedroom or study that is close to other bedrooms).  All recommendations made thus far are great options, it comes down to your actual space, purpose, preference and parameters/limitations.  Happy hunting!

@yyzsantabarbara I have Focal Electra 1028 Be speakers in my primary listening system in a large room (20' x 30') and could not imagine them in a smaller space.  The Kanto is the replacement for the Electra, so I would expect a similar performance/price ratio.

Pulsars, but look at the Usher lineup. Oh, Living Voice too.

Quads are a great idea! The speakers serviced by Kent in KC are supposed to be great. A friend is using stacked quads like this and he has had everything (even IRS)  original Apogees, Dali Megaline etc. He uses the Spec Gear from Japan and loves them (see Jeff Day’s Blog) with his Quads.
Where are you in Southern California?