for a decent amount of bass with SQ in mind .. I'd go for a PROPERLY powered 10" Alpine Type-R in a sealed box powered with any sufficient clean amp - any alpine, kicker, rockford, jbl, jl, phoenix gold, orion, etc. amp... with amps do not cheap out - clean power makes subs happy.
when chosing or building a box, make sure you look at the manual for the sub you buy for box specs - theyll tell u what size enclosure to have for SQ or SPL applications...
when getting a new sub, break it in - 5 or 6 hours on lower volume (straight) will do a good job.. the best way to break in a stereo is through radio static
but really, just goto an audio store and listen to the subs and find something you like for the music you listen to - find a good amp that will power it nicely (that meets or exceeds rms rating) and you'rre good to go.