I have been using Wright 2A3 SET amps with Klipsch La Scala's, and have found the Quicksilver speaker cables to be superb. Definitely go with the silver.
Oxygen free wire with good insulation should do you fine. The stuff at Home Depot is very good and very cheap. Read Roger Russell's article on speaker wire and the tests McIntosh labs did at one point on various speaker wire. Here is the link to the article; it is quite comprehensive.
The important thing is that your gauge is adequate for the length of the run.