I will probably next build the Theater 4, Theater 7 or the 10 folded horn. I would like to build a folded horn (just because), but one reason is so that I do not have to use them in a corner if I choose not to. Also, I really do not need a profesional grade speaker, I will be useing them for simple home use.

The Theater 7 corner will give you more sensivity, more bass extension and plenty of db's for home use. They are also cheaper and will allow you to try out that SET that you are talking about. Once you try the SET with a speaker like the Pi's it may just open up a whole new world for you. Hi sen speakers really shine with tube gear.