Sadly my subwoofer situation is up in the air at the moment. But luckily I have the M80's, which completely satisfy my bass thirst while listening to music. Not that the EP800 was useless for musical recordings, it still added even MORE, and I loved it. But for music I can live with just the M80's all day long without any withdrawl symptoms sneaking up on me.
And as for the 'sub 20 hz' statement, I think it was Jakewash that pointed out that what most of us bass-heads consider 'deep bass', is really the 60 - 90 hz range of the scale. Sub 20 hz is the stuff that rattles the walls and the neighbors walls, but you don't hear it. It's really great for movies, but not much music hits below 20 hz. And the thing I found out about subs that do sub 20 hz really well, is that they don't necessarily do 60 - 90 hz outstandingly well. I say this because I was under the same impression as you, that I needed a sub to go as low or lower than anything else out there on the market so that I could experience the same chest pounding bass that I used to get out of my car system. Turns out, the subs in my car probably weren't reaching half as deep as HT subs can go, but they hit me in the chest so hard my heart fluttered. So I was looking behind the wrong door the whole time.
To sum up what I'm trying to say here is, don't think if you can't buy a $2300 dollar subwoofer that it's not worth buying one at all, because the sub that's going to do what you want it to do may only end up costing you a fifth of that my friend!
(and yes, DIY subs can get you loads of performance for a fraction of the cost of a manufactured unit)
