Wire is Wire
Yamaha 665 90w per channel with Klipsch QUINTET SL 40w speakers
should I use 16/2 stranded white lamp cord to run speakers ? $50.00/250 ft
or is solid copper wire better, say 12/2 or 14/2 solid romax wire ?
why is speaker wire any different form stranded lamp cord ?
speaker wire is stranded 12/2 or 14/2 or 16/2 yes ?
It's not really - wire-is-wire IMHO gauge is the key factor and in 95% of installations 14 gauge is all that is needed.
However, if you use solid romax wire, it is not very flexible, especailly 12/2 and looks pretty crappy when run as speaker wire. Speaker wire is usually stranded for flexibility and is much more asthetically pleasing to look at.
You can put you own connectors ( e.g. locking banana plugs are great) or use
bare wire.
For a reasonable price you can get very good, yet inexpensive cables from monoprice.com or bluejeanscable.com
However, you might want to buy some Pear Anjou speaker cables and compare them to Romex and let us know how they compare

.
You can find more about Pear Anjou cables at :
http://www.pearcable.com/sub_products_anjou_sc.htm
Peace,
Forest Man