I just went through this on a friend's car he bought. First thing to do is find out if the previous owners replaced any components (struts / shocks / coil springs). Some of the lower end springs are just horrible when it comes to ride quality - or I'm just getting old. Also a lot of the lowering springs have higher spring rates and you need a better rebound rate on the strut / shock to help with that.
The most expensive struts / shocks in the world will ride like garbage on too stiff or too soft of springs and they don't match up. I'd also check tire pressure believe it or not.
As for brand recommendations, my '04 is riding on 15+ year old Eibach springs and what look to be 90K mile stock struts / shocks and I'm surprised how good it rides. I've had great luck with Bilstein struts / shocks in the past as well.