optical or coaxial audio cable?

For sure, the Coax connection is prefferable when sound quality is what matters.

Experiment. I've found Toslink very superior to coaxial in one system using an Assemblage DAC. More open with cleaner bottom end. I use a Nordost XLR in another system. Good luck.

I have a Sony DVD player and a Yamaha receiver running my B&W 602's for now. So I don't have a really high quality amplifier. I have the optical hooked up right now. Will I notice a difference even with my low price receiver?

Don't bother until you get into higher end gear (seperates). I also had a Yamaha for a while and the optical was fine. I now use coax with my Innersound amp and Martin Logan speakers. Coax is a slight improvement...

Happy listening!

You can get a really nice glass ( don't use plastic) fibre optical cable from wireworld for around $100.00. this is not much of an investment. Also, get yourself a decent coax and plug them both in. You should be able to switch from one to the other and you can decide for yourself. I have the Acoustic Zen coax and I like it. I understand the Nordost is quite good, too. You can sell any of these on Audiogon for not much of a loss, later.