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

Agree with the Raidho suggestion (or Borresen if you can swing the funds). Consider the D1 or possible even D2 if it's a dedicated room. Nice thing about Raidhos is they're designed to be placed wide apart and close to side walls (though they need 3+ feet from front wall). They're amazing speakers with a glorious tweeter. Smaller Vivids are also quite nice in a smaller room.
I moved from a large room with full range Peak Consults (and subs) to a smaller 13'x16' room. Both my Raidho D2 and Vivid 1.5 sound great in this room. Bass is solid and tight to 40Hz. On some music I miss the extended bass I was used to, but for most music it isn't an issue (either that, or I've adjusted). Room treatments and bass traps can be a great help if it's a dedicated room. 

Other possibilities: Though not at the same sound level as Raidhos and Vivids, the Larson speakers work up against the front wall and work well with room modes. I heard them at a dealer and was impressed. I'd also consider Kii standpoints--their DSP evens out the bass response and goes quite low. Haven't heard them but would like to...