Bicycle Tutor

Any suggestions or good descriptions of any differences that might be found and more importantly, how to tell the difference when you look at it, especially online? Does one want galvanized or stainless, or teflon coated? What about how the cable is made? Can you only get twisted strand or do they make solid cables?
Basically is there anything particularly better or worse about the choices out there?

Pretty much any cable will "work", but the better cables do work "better". Stainless and coated cables will not rust which probably is only a big deal if you are in a wet climate. If kept properly lubed, normal cables should not rust for a long time anyway. The teflon coated cables slide smoother through the housing. This means more responsive brakes and cleaner shifts. Won't make a huge difference, but you can feel it. Higher quality cables also tend to be wound tighter so they stretch less under load. This also helps both braking and shifting performance. I think shimano makes a slightly thicker brake cable for their MTB systems than for road. But I'm not sure what groups use the thicker cable. Finally, don't overlook good cable housing. Cheap housing compresses under pressure which will make your brakes mushy and gears hard to adjust.
I'm a big advocate of spending money on good basics like cables, brake shoes, and tires. They have a much bigger impact on how the bike performs than shaving 4 grams with a titanium bolt ever will.
All modern cable are twisted strand. I think some very early index shifters used a solid cable, but no more.