Thermionic four π speakers are great, but they're huge. That's the only complaint I ever hear about them, so if you've got the room you should really enjoy those speakers.For your amplifier, the most common speakers are the Theater Series four π's, Thermionic Series three π's and Studio Series two π Speakers. Each of those is excellent too.
I suggest you make a mock-up of each of these speakers with cardboard or posterboard to get an idea of their size. Decide which is best for your room and let me know and I'll send you the plans.