vintagebob -
The 440 and the HT2-TL go together like PB&J. I will admit that I haven't spent very much time with the 2 channel setup. I've spent the vast majority with my SongTowers and sub doing the movie thing and home theater pass through. I will probably spend some significant time this weekend (starting tonight) with the HT2-TL's. From what I've heard so far, its a great match, and I really like all the reserve power. I never get past maybe 9 or 10 o'clock on the volume level on Frank's preamp and its playing pretty loud. I use the Low Gain toggle as well alot, and I'm probably going to leave it on all the time for fine tune volume control. I've cranked it up fairly high as well, and the music gets louder, not messier.
I think the only concern I'd have about mixing a 440 and a 240/3 is perhaps volume leveling. It seems like the 440 is going to drive a speaker louder with less gain than a 240, and so you might have some uneveness in your 5.1 sound field. But maybe the effect is negligible or you can use the trim levels to compensate.