Wow, those EP100s look like a blast from the past:
http://www.humanspeakers.com/e/epi100.htm
It's too bad the TST3s didn't work out for you. But I do understand we each have our own tastes for sound. What I will say is that I really don't think TSC speakers (particularly the towers) sound good with a Denon receiver. Since TSC speakers in general seem to be optimized for midrange clarity, mating them with a receiver that itself also emphasizes midrange clarity could be overkill. I know because that's what I demoed my TST3s with is my former Denon AVR-3808ci. While I certainly understood what all the rave was about the speakers, I find that the thin sound from my Denon receiver just didn't help the speakers any. The same case was when I was using my old Paradigm Monitor 7s with the Denon too as I remembered the sound to be more full when I used them with a Yamaha or Pioneer receiver.
To me, I think forum member Lord Of The Rings best describes receiver sound here when I asked him what he thought of Onkyo and other brands:
"Ok, How do I found my Onkyo receivers (876 & 805) compared to the warm sound (in general, not the new ICE power design) of Pioneer, or the Mid emphasis and reserved sound of Denon receivers (even bordering on thin, lacking some meat in the lows and also in the highs), to the fuller and cleaner sound from the Yamahas, with that more natural and well balanced sound from across the frequencies, nice lows, very articulate and clear mids, and a quasi sweet high end (still talking about Yamaha here in general). My Marantz is warm too, with a full sound and more relaxed compared to any other receiver. The sound is musical, inviting anf float very nicely, with a nice and wide soundstage and some nice depth too. I also found the Yamaha adds height too (must be those two front presence speakers ). Ok, let's not get lost here, I said that I will be very brief. Now, my Onkyos? The sound is clear, clean, neutral, punchy (so is the Yamaha for the punch), hard to describe at times, maybe because of that type of neutrality, where no specific frequencies are overemphasised. For me, it sounds right, powerful, dynamic and very pleasant with good articulation but lacking that last minute resolution. Maybe the Yamaha here is the winner for resolution that is natural. But the Denon and Marantz also have a decent dose of resolution. I must admit though, that to judge resolutioin properly, like any other audio attributes, a big influence comes from the recordings. But I'm just shooting here my overall impressions."
I've have since sold my Denon AVR-3808ci and got a deal on a Pioneer Elite SC-07 and I am so glad I did so. The output of my Paradigms are now again warm, smooth and full sound that the Pioneer amps so wonderfully produce that to me just wasn't there with the Denon. LOTR hit the nail on the head when he said "the Mid emphasis and reserved sound of Denon receivers (even bordering on thin, lacking some meat in the lows and also in the highs)". The only Denon I've owned that I really loved the sound of was the AVR-4800. Sadly, I think the only model you can get that kind of sound from now is with a 5000 series and I just don't have the money for one of those. I don't think I'll be going back to Denon anytime soon.
With all that said, I do think the TSC towers would sound really good when mated with the right receiver. The TST3s probably arguably should have deep bass. I think the only speakers I that I've heard that I think sounds fairly good with a Denon receiver are Definitive Technology BP Towers. My buddy has BP10Bs and they get pretty low (they're rated down to 20hz). Still, I don't like the idea of having to find specific speakers to sound good for a receiver. I'm a compulsive upgrader and I've gone through around 8 receivers in the past 10 years. The brand of receivers to me that have good overall sound characteristics that sound good with most speakers are Yamaha and Pioneer in my experience. Anyway, I recommend that you consider changing receivers as well to find that full "smooth" sound that you're looking for with modern speakers.