We have a lot of horn customers. At 100db, its nice to have a little power behind the speaker, but in most rooms what that means is likely not going to be more than about 60 watts. For that matter, you'll do fine with only 30- and especially if you are going to use a transformer-coupled tube amp, 30 watts or so is where the best performing tube amps are. More than that in a push-pull design and bandwidth becomes limited.
You could also use an SET, but in many rooms most SETs will not have enough power. With SETs you want to have the speaker efficiency such that the amp does not need to make more than about 20% of its rated power; this is to keep distortion down (SETs typically make about 10% distortion at full power, which can color their presentation, but at much lower powers their distortion becomes hard to detect even with excellent test equipment).
FWIW my speakers at home are 98 db and 16 ohms; I find 80 watts to be an ideal amount of power. 99 44/100% of the time its impossible to clip the amps.
So a lot depends on your room size and how lively it is, as well as how far you will be from the speakers and your own listening habits. If I were you before pulling the trigger on any amplifier I would audition a number of amplifiers using a list of cuts from your music library that show off various aspects of what a stereo should do: soundstage, dynamics, bass impact, detail and so on.
