Considering used towers under $1000..

They are respectable but for sure needs decent powered Subwoofer, also rebuild the Xover with higher quality capacitors 
bare minimum very good upgrade. If you or a friend can solder.

Another "by the way":

It is unlikely that any of the speakers in the range you are looking for ($1000 used, probably at most $2000 new) will give you really deep bass. Others may add to that thought if having more experience as there are many speakers I have never heard (of).

I think audioman58's recommendation may be what you need, if bass is of importance.

"It is unlikely that any of the speakers in the range you are looking for ($1000 used, probably at most $2000 new) will give you really deep bass."

The SVS Ultra Towers (with two 8" woofers each) claim to go down to 28 Hz. Not sure how 'deep' that is but to my ears 32 Hz is low enough for the music I enjoy. 

Might be able to find a pair used (or closeout) for around a grand. 

towertone,

That is a good news. I have no idea where it starts feeling like a deep (and strong) bass so input from others is valuable. On the other hand, and for whatever it is worth, Monitor Audio Silver 6 I suggested are claimed to go to 35 Hz but they simply do not feel like having a major bass in the room I have listened to them in and associated equipment (Yamaha 501? 701?). Maybe they do, it just is not a major "oomph" some people crave. It is good enough for me, though and I feel they sound really good overall.

Why not try some jbls?.... maybe a pair of L100s. My L80t3s were only like $250.