Best Klipsch floor standing speaker

How do you define "best"? 

If you have the space, I'd look at a pair of La Scala 2, $8K retail.  After that, the Cornwall.  Others to consider would be the Belles, Chorus, and Forte.  If you have a smaller space (and a subwoofer or two or four), the Heresy are nice.  There are a couple of threads on the Klipsch Community message board about rankings of Klipsch speakers.  Surprisingly, opinions vary!

Epic CF-4 version 1. I have also owned Conwalls (late '80's) Klipschorns (late '70's).  

Those CF-4s are pretty close to unobtainium. Especially V1. I had some cf-3 that were version 2. I think those are the only thing that I've sold that I kind of regret letting go. They were kind of hard to sell too which seemed odd but a lot of people don't like big speakers.

big_greg,
Yes, they are. I came across mine in a funny way. I was reading random reviews on audioreview.com years ago and happened on a review of them by a man who owned them and was so emphatic about how good they were that I went looking for a pair. I found them on ebay, and even though I had just bought my second pair of TDL Monitor speakers after regretfully selling the first pair years earlier, I bought them on a hunch for $900.00. I was shocked the first time I listened to them, and immediately sold the TDL's...again. 
They have surpassed the performance in most categories of the other 17 pairs of speakers that I have owned, including a pair that was highly rated by Stereophile and would be an apples to apples comparison, the JBL Array 1400. I bought them as well after owning the Epics for about 5 years. They were beautiful, and very good, but not as good as the Epics.
They were a truly amazing creation by Roy Delgado of Klipsch. 

That's a good story. I had some KLF-30s for quite a while after looking for some for a long time. I liked those a lot as well. Better in some ways than the CF-3, but the cabinets were not very well made.  I let those go not too long ago. I'd like to get some Quartets if the opportunity presents itself.