Well I think it comes down to the circumstances and brand as well. I would buy without listening if they measured exceptionally well on the Klippel or an anechoic chamber, but only if I couldn't audition them. Preference would be to audition and that audition would be best in the room they're destined for, but at the very least at a hi-fi store.I am actually surprised to see how many of us purchase without listening first.
That said, some speakers are not available online or via chain stores, rather from specific hi-fi stores or even direct from a boutique manufacturer.
I wouldn't consider any speaker that I had not seen independent and trustworthy measurements for.