Yeah, Thiels can be tough, but I suspect there are many speaker choices out there that would work well with that amp. An easier load and higher efficiency speakers on paper likely provide the greatest upside.
Of the ones you mention, I think mbl is the only line I would have major reservations about in that I suspect these are no easier to drive than THiel and maybe even worse. They tend to meet their potential mainly with only the biggest and beefiest SS amps.
IF its teh omni sound you are after, OHM might work well. My OHMs did very well with a modest power 80 watt Tandberg receiver once, and with a 120 w/ch Musical Fidelity power amp. Room size and acoustics would be a determining factor for how far you can get with a good 80 watt amp driving OHMs. Impedance measurements I have seen for the OHMs indicate impedance dips to just below 4 ohms in the bass region, not horrible by modern standards for most good SS amps, but not the easiest either.
Audiokinesis is another innovative line I like on paper a lot (have not heard) that pays special attention to value, soundstage, imaging, a large sweet spot, and ease of setup, all things that OHMs are known for as well, plus I believe to be a fairly easy load to drive as well in general, perfect on paper for an amp like that maybe. I'm thinking if there is a more conventional and affordable speaker line out there that might have a chance to lure me off my OHMs someday, AK could be it.
