The SVS SB-2000 sealed subs were $499 del'd again just recently and a superb steal for that. I have two from a year or so ago and and they're great. There are some other great inexpensive sub mfrs out there as well. Two small SVS sealed subs would be nice I think.
(Also have one SVS SB-3000 and REL Storm III in the room for 4 ttl, D.B.A.)