I had a pair of the powered EON 15's and I replaced them with a pair of powered G2 EON 10's. The 15's were overkill for me... the rooms I play are usually small and I play at near-acoustic levels. I use my EON 10's for both mains and monitors, by placing them on the floor at an angle behind me. They seem plenty powerful at 175 watts each and they carry bass surprisingly well (being on the floor probably helps). The newer G2 EON 10 powered models have more power than the originals did. They are fairly common so I tried them out at a music store with an arranger keyboard before I bought them... they sounded great. I bought them new, I think for around $450 each. I also recommend the carry bags that JBL makes for them, which makes them much easier to tote (the EON 10's have a strange and uncomfortable hand hold on top, the bags have a real handle) and less prone to scuff.

I also have a pair of the original non-G2 EON powered subwoofers that I have used with the EON 10's in auditoriums and outdoors. The EON 10's feet fit into the holes on the top of the subs so they stack great. So if you really want to cover the bases (or basses) and can handle the cost then having both the 10's and the matching subs is the most versatile way to go.

JBL EON's are not inexpensive, but they are really well made, sound great and will last for many years with a little care. They also have good resale value (I had no trouble selling my old EON 15's).