Bang for the buck

There are some very good suggestions here, but I'd like to weigh in with my own: Ryan R610. I've owned a pair for several years now and have not really been tempted to upgrade. On the used market they sell for way under $2K (they're about that new), but the problem is that they almost never come up on the used market. That's how good they are. Of course, as with any speaker, the electronics driving them are a factor, as are the cables (and in this case, the jumpers unless you bi-amp them) but for musical, balanced, non-fatiguing sound, very few speakers in this price range can beat them. 

If bang for your buck is the main consideration, some sort of DIY kit speaker can  offer an amazing value by using the same drivers that are found in expensive speakers ($25,000+).  

I don't review specs, they are flawed in many ways  believe.  At $2k budget Wharfedale Linton 85 come to mind. Unless you want vintage.

I don't want vintage,  the croton tdx are definitely bargains,  but I would not be inclined to build them myself. The bang for the buck I was thinking of was great sounding speakers that sell for irresistible prices on the second hand market. As someone already pointed out, sometimes those great speakers are hard to find on the second hand market because people tend to keep them. I like the idea of getting a Salk veracity ht2 vs the songtower (both are great I'm sure, but the ht2 is probably better but bigger.). I do wonder if for a small space (15'x11') if the cabinet space of transmission line design takes up more cost and space than cheaper and simpler port designs.

I have no idea if the Salk songtower or veracity ht2 would walk all over the Arendal 1723 speakers, but those 1723 seem to be on the current speaker "hype train" , and I'd be lying if I said I wasn't curious about which choice would be better. (Largely due to the fact that I've heard neither and I have absolutely no clue because of so many available options)