personally i use this 6mm stranded (why 6mm? because i had NO IDEA how big the cable would be and now i have HUGE speaker cables gah) van damme blue series stuff for my speakers, £7 per cable including the soldered-on plugs at both ends, DIY woot! anyhow, flexible, as solid wire would be a pain in the arse, but for internal stuff i'd use solid as it would be easy to route and take corners with. SQ? ever tried using a single strand of thin copper wire for your speakers and comparing the difference with the entire wire? hell i just unplugged an optical jack from my dac and shone it in through thin air from 1cm away and heard absolutely no difference in the sound at all - hurrah for digital. (this is my cable 1m Pure Optical TOS Link Cable TOSLink Lead Digital UK on eBay (end time 20-Jan-10 10:19:52 GMT), £1.73 & free p&p, buy one and compare it, it costs less than busfare) perhaps i'm just odd in that i would rather reverse tweak (it's free) and see, if, by the popular logic of audiophilia, the sound gets worse if i totally make things as bad as they can possibly be before the system won't work at all. i believe the fancy posh latin phrase for this would be reductio-ad-absurdum give it a go!