Eclipse Aluminums are awesome subs, but a little pricey. They can be had for a couple hundred each though, have awesome sq, and 2 12s would be really loud (I had one Aluminum 10 in a small sealed box and people thought it was a 15 before looking). Titaniums are quite a bit louder, but the Aluminum sounded slightly better (althought it may have to do with my Aluminum being a 10 and the Titanium being a 12). Also Titaniums are real spendy, and they suffer from lack of cone area. Very impressive subs. And the single piece polished metal cones look great, some of the best looking subs on the market imo.
People seem to be having problems actually getting their ED subs, so I don't know if I'd go there... I'd check out Resonant Engineering subs, I've heard a lot of good things about them. Also I've heard a lot of good things about Treos, but haven't actually heard an RE or Treo so I can't really comment on them.