Thank you Nick for opening up your beautiful house to all of us and the delicious "well-done" hot dogs. It was absolutely wonderful getting to finally meet everyone in person. It's one thing to discuss AV on a forum; it's a whole other world getting to experience it with a bunch of great people first hand. I feel bad not helping to clean up. We sure made a mess out of your house.
Like others have mentioned, the Submersive was really impressive. I agree with Eric in it's ability to pretty much plug and play and, at the same time, produce immense levels of clean bass.
The dual LMS powered by a LG clone still produced the most tactile feel as can be expected. In the WotW scene from the demo disc when the ground was rupturing, the tactile feel that the dual LMS provided felt real as if the ground beneath the couch we sat on was about to crumble. As with any DIY, the LMS can benefit greatly from some EQ and tweaking. I feel the LMS still has the most potential out of any sub I've heard and definitely recommended for those who are more hands on. *I have a pair of LMS so I may be biased.*
The Rythmik E15 is the other sub that really impressed. For music, I'd still recommend a Rythmik. The output for its size is spectacular, especially in such a large open room. Switching to a movie; however, was just a bit too much for the single 15" driver in that room. As expected, the bass from this sub was extremely clean.
Conclusion (my recommendation):
For music: Rythmik
For casual room*: Submersive
For dedicated HT**: LMS 5400
*Casual meaning a room most people would have: no acoustic panels, open, etc. **Dedicated HT meaning a controlled room: acoustic panels, enclosed, etc.