I'm using La Scala II speakers. I guess Klipsch are the most well-known horn brand. I would never advise anyone to buy these, or K-horns, without a home demo. Really, any speaker. But definitely these. Problem with that is they are so large it's difficult to move them about--it takes two people to really do the job. Of course the corner horn requires very specific placement, so unless you are architecturally set up for it, you can't use it. The La Scala is a little more flexible in that regard, but doesn't go down as low in the bass region. Both are physically imposing. Especially the La Scala which requires a very large space. The K-horn can sort of be 'hidden' in a corner.
Both are not what I'd call cheap, but in the context of horns, they are not exactly expensive, either.
Power-wise, you can use the proverbial 8-watt SET and still get loud sound. I use a low noise 100 watt/ch amp without problems. I don't know that you would need much more than that, ever.