Music or home theater? Budget?
Home theater - SVS Ultra 13. You want big displacement for home theater. Ie 12-13 inch minimum.
Music - REL & JL Audio. Usually prefer 10 inch sealed. 2 subs better than 1 big.
JL's are really good enough for both home theater and music. They have have a new affordable line called "Dominion". USA made, excellent build quality and customer support.