Anyone with a high-end home theater sans sub?

Adidadi - the Meridians are nice speakers. They cover nearly all frequencies you'd find in most music (excluding techno and similar genres), and they have very good mid-bass slam.

For action/adventure/epic movies, you are missing out on a substantial amount of low-frequency information.

It would be worth borrowing a sub to see what if any difference exists.

Yeah, you defintely need powered sub(s) to help that sytem respond like the soundtracks were designed, that's all. If you like what you hear, then it's all good. However, you are indeed missing the full impact of what's intended...nothing more, nothing less.
To say what you have is better or worse, is subjective. But the companies mixing your soundtracks would definitely agree you don't have it set up right.

You can't make a blanket statement like "All home theater needs a sub." My main speakers are Meridian DSP8000s and there is absolutely no need for a sub - they are flat to 18 Hz in my room, up to 118 dB (God forbid). My Meridian 568.2 is programmed to send all frequencies below my crossover setting to them and, believe me, it's high-end home theater.

Rex,
As John points out about his DSP8000's, I used to have these 8000's in my theatre and swapped them out for what I have now. When you have these speakers; there is NO need for a sub. They are full range. My system now is even more dynamic and bass accurate then when I had the 8000's in my room, because they were over powering. I have had a Revel sub in my system and as good as it was, with my current 5 channle full range set up, I do not miss a thing.