Hi Saffy,
In response to your questions:
1. Both the Druid and Abbys are great speakers, especially Abbys for the money. I think the two do really well in small to medium sized rooms. Both benefit greatly from a subwoofer. Although, the Druids deliver surprisingly deep bass for a cabinet that is only 6.5" deep, really perplexing how they do that.
Zu seems to be one of those products that evoke strong responses, both pro and con. Some of those who dislike them have actually heard them, a lot have not. You have to decide for yourself and Zu's 30-day money back guarantee assures just that. Not many other manufacturers are that generous.
Oddly, we tried my PX-25 with Abbys but actually preferred the $800 Almarro A205A with it. The A205A is a single-ended pentode (SEP) amp that has sonic performance leagues beyond it's price. Paired with the Abby, it is sublime when you take cost into consideration. A few cheap upgrades to the Almarro make it a real giant killer.
As for other speaker options, please let us know your room dimensions, average listening level, and how far you sit away?
2. Low-power, high sensitivity, systems are far more revealing(IMO) to component and cables changes than high powered systems. Noise is also a big problem. For example, when I had 90dB speakers, my system was dead quiet. But, when i switched to 97dB speakers and <8wpc SETs, it became glaringly clear that I had a loud 60Hz hum problem in my household electrical system. The hum was clearly audible at my listening position 14+ feet away. I had to re-ground my breaker panel and then use balanced isolation transformers before my audio system before I could get it truly quiet. Never knew the noise was there with 90dB speakers.
I've also found that cable changes are far more pronounced with the high-eff system.
3. If you only have one source, then no need for a linestage. Whether the PX-25 passive will work well for you is really dependent on the output of your cd/turntable/tuner, etc. The PX has an input sensitivity of 0.7V, so anything with 1.5V output will do really well as long as you keep interconnects short. I probably wouldn't use anything that has under 1.2V output, a little headroom is always good so that the sources output stage isn't stressed at all - they distort badly when pushed hard.
