You don't indicate how long the cables need to be, or whether it will be a single or bi-wire setup, so I am going to assume for the discussion that 10-foot runs will suffice, and that you do NOT need bi-wiring.
On that basis, and given that this is a second system, I suggest that you consider the Alpha-Core Goertz MI2 (or maybe even MI1, given the power output of the amp) cables. They have very low impedance (the MI2 has an impedance of only 2.5 ohms), so they work very well with both tube and solid state amps, not to mention low-impedance speakers.
For more info about Goertz speaker cables, prices, and a list of dealers (you can also order directly from the factory, which will also do the terminations), here's the Web address for Alpha-Core's Goertz speaker cable line:
http://www.alphacore.com/mispeaker.html
The other cable choice which should also work very well in your (second) system is Kimber Kable 4TC or 8TC. These cables do a lot of things well, and have no major deficiencies in performance.