I am trying to tame the 'clankiness' of my bass and wonder what strings you use. I find the nickel rounds too harsh (DRs). and the TI flats are too mellow. What can youse guys suggest?

You might want to try a ground round wound string. The brand I use is GHS Brite Flats. Most of the other string companies also offer a GRW. They are brighter than flats and quieter than a round wound.  
 
Keith

I think d'Addario still makes their half rounds.  Same idea.

Yes, D'Addario still sells the half rounds.  I started using them 30+ years ago on my Rick and recently got some for my Epics.  I really like them.  They are about $22-30 depending on where you get them.
Rich