I listen to classical, film scores, classic rock, world music, jazz, electronic, new age, vocal.... a little bit of everything.
But mostly classical. Piano, guitar, harp, symphonies, string quartets, organ, .... you get the idea.
If I listened for half an hour I'd take the LS-50's.
If I listened for two hours I'd take the Harbeths.
After listening for four hours I'd take the Spendors. They sound better at lower volumes (something the Harbeth is also very good at). They have a wonderful presentation on symphonic music. They layer the soundstage nicely. I never get tired of them, but at first listen you'll think the others are more 'exciting'.
After living with Quads for three years I've come to appreciate low-level listening and total lack of any 'fatigue factor'.
These are all super good speakers, it's close. But I do love the Spendors the best.
Edit: One last thing I almost forgot - they're the best looking of the three!