Shawn
Glad to hear that you'll be getting SongTowers. Did you ever get to compare SongTowers and HT3s at Evan's?
I'll also add my 2¢ for the ribbon STs. When I heard the ribbon vs. dome STs some time back, I thought the ribbons sounded a bit cleaner than the standard dome ST. You would most likely notice that with any music that emphasizes voice or a few instruments with an otherwise quiet background. With music full of sound, like a symphony playing at full tilt or hard rock, you might not notice the difference as easily.
If you have the budget for ribbon SongTowers, (I'm guessing you do since you were thinking of HT3s at one time) I'd say go for it.
Richard