Dynaudio Audience 52 or 52SE, depending on how much you want to spend. Both are 4 ohm speakers, but they are very linear and easy on an amp. These are truly fantastic sounding speakers that are very system friendly. Revealing and extended, but never etchy or fatiguing. Wide and open sounding with a low end that will leave you scratching your head.
These aren't merely 'different' sounding speakers, these are clearly superior speakers that wouldn't be out of place in a main system.
The Sonus Faber speakers are very nice, just do a double check on their impedence plot. I could be mistaken, but I seem to remember that they drop considerably below 4 ohms and aren't very sensitive. Nice sounding if they will partner up with your receiver.