aprox 1500 sq ft house.
The distance I mention is from my ear to my speaker when sitting back on the couch. 10 ft will be fine.
I have the ep 500 as well. I am going to add a second ep500 or probably an ep600 very soon. One ep500 does fine in my room, I just want MORE
I say go for the m80's if you can swing it and your receiver is 4ohm friendly.
If, not I am sure you will be very happy with the m60's from what I have read around here. I knew If I got the m60's the upgrade bug would kick in.
I didn't think that Would be the case with the ep 500 vs. the 600 (plus I could not afford the 600 at the time)... but now the upgrade bug is kicking in a bit... rather than trade in the ep500 I think I will run dual subs (one 600 and 0ne 500, or maybe just dual 500's)
see the pics in this thread for my setup:http://www.axiomaudio.com/boards/ubbthreads.php?ubb=showflat&Number=189625#Post189625
Also, the house I auditioned my m80's in was considerably larger than mine. The living room was a little larger, and the ceiling were 9 ft- IT openened to a large kitchen/the rest of the house with very tall ceilings.
I think my m80's sound every bit as good in my smaller room as the larger one. (Actually I think it sounds better in my room- but prolly just b/c I paid for these speakers and not the others!
Bottom line- Don't let the size of your room keep you from getting the m80's- that is really not a factor at all- 2000 cf is plenty of room for the m80's to come alive in.
Gotta jet- going to listen to one more song on my m80's before I go back to work