I can understand how sound quality could differ in solid core interconnects but does it really make a difference in brand when selecting digital cables (i.e. No name, Monster, PureAV, and a slew of others)?

I wouldn't recommend over-spending in this category. You just need well made cables. For optical, I'd be hard pressed to change from Outlaw's PDO for any application where the 1.8-meter length is sufficient. For coaxial, I've got one Outlaw PSC and one Blue Jeans digital audio - both are good quality, reliable cables.

I've been recently researching this area myself. It's been the subject of fairly passionate debate. There's one school of thought, which is "bits is bits" and neither the cable type (toslink vs. coax) nor brand should make much difference.

The other school of thought is do not use toslink if you can avoid it and get a good coax cable that has a true 75 ohm RCA connector. The reasons? From what I can gather: (1) the connection on toslink is not as good as coax; (2) toslink is more prone to jitter; and (3) coax has a wider bandwith. There's also something about the inherent weakness of toslink converting light as the input signal, but I can't remember the particulars of the argument to do it justice.

Anyway, I haven't done any A/B comparisons of the two. However, I am currently upgrading cables throughout my system and plan to make a length of coax and compare it to the toslink I am currently using on my Oppo DVD player. If your a DIY-type, the digital cable made by DH labs (D-75) with their 75 ohm RCA connectors can be had pretty cheap online. (BTW, I do not work for or have any affiliation with said company.)

I plan to order this combo soon and will report back my results if anyone's interested. Be forewarned, I'm the same guy who heard differences between my stock power cord and an aftermarket brand.

I've read that the jitter issue with toslink is the same as that with the coax, in that the S/PDIF interface itself uses its own clock signal, separate from the clock signal coming off of the source, causing some "confusion". The result, from what I've gathered, is less apparent than the tic-tic sounds caused by jitter from a d/a. However, if you read this article by Bob Katz, it says that almost all jitter is subtle at best.

Flying in the face of audio idolatry, I suggest buying a relatively cheap, well-shielded coax cable, since they're overall cheaper than the optical. Radio Shack is usually fine, so is making your own from RG59, although if name brands appeal, you can find many used audiophile RCA video cables on ebay very cheap.

One more bit of information about toslink, should you go that route, is to use a glass-based cable. I found this post on audioasylum.com that summarizes the issue much better than I can:

"Early Toslink cables were poorly designed. They used plastic insides that often developed cracks and caused problems for the fiberoptic light. This raised its head as increased jitter in the signal and many heard this effect on the sound. Thus, cheap Toslink (and all Toslink in the end) got the reputation of a poor connector. As time went on, as it always seems to do, Toslink fiberoptic cable was manufactured along the lines of the ST (AT&T) fiber cable. High-End cable companies offered Toslink connectors manufactured with glass on the inside that was more robust and began polishing the ends (the connectors). Voila, better sound for Toslink. As for coax digital cable, the materials and design have just as much an effect as Toslink materials and design. A great deal of the sound depends on how well the interconnected components are grounded. Which is better? Technically, the coax has a higher bandwidth than Toslink and this is a benefit. The ideal coax connection is better than the ideal Toslink connection. But, when do we have ideal when dealing with electricity (or light for that matter). You need to try each in your system and decide for yourself."

I wonder if that remains true or if it is over-reacting to older problems - glass fiber cables are still pretty rare (and pricey), but good optical cables are available from a number of sources that still use plastics of various types which avoid the problems described in the Audio Asylum post. Of course, I've been dealign with design requirements driven by over-reactions to old problems a lot this week, so I may be a bit biased...

Could be.

I don't know much about what's out there in the way of toslink, but I did come across this glass cable from Sound Professionals that seems reasonable ($50 per meter): http://www.soundprofessionals.com/cgi-bin/gold/item/SP-TOC-99HQ

And here's a review from an audioasylum poster that really seemed to like it: http://www.audioasylum.com/audio/general/messages/233584.html

$50/meter for optical is not an unreasonable price, but it's still a fair bit more than the $20 for Outlaw's very nice 1.8-meter PDO and $14 for a 3-foot Blue Jeans optical (both of which use some form of plasic optical fiber). I also find myself wondering why an optical cable would be directional, as mentioned in the Audio Asylum review - there's no grounding that I'm aware of in light transmission.

Good point. There was also nothing I read on Sound Professionals' product description that would indicate it was directional.

Another cable I stumbled acorss with a bit more searching is this one: http://www.worldofcables.com/oscatalog/CreateHTMLPagesItem/45456.htm

Apparently, it has more strands than the Sound Professionals cable and is a bit less - $38.99 per meter. Frankly, at those sorts of prices, it would be interesting to do a shootout of a good coax-based cable, like the DH Labs D-75, and a glass-based coax like the Sonic Wave.

I may do just that. The winner would go on my DVD audio out and the loser could feed my CATV audio connection.

Oops. I meant to type "glass-based toslink."