Request Speaker Cable Recommendations

I have yet to figure out how to compare speaker cables, except to buy 10 pair to compare in my own system. Instead, please give me your recommendations based on the following:

I recently moved my system, so I need at least 15ft of cable (about 4.6m) to each speaker. I would prefer bi-wire cable, but not picky about type of connection. I tend to lean towards a more forward, present sound, detailed and quick, yet full, with preference for extension in both frequency extremes (I'm one of those guys that likes treble).

Tends to make me think that a combination of silver and copper would be ideal? Only problem is, and here is what I expect will separate the men from the boys, I would like to stay in the $300 range, for used cables, if possible.

My system is:

Speakers: NHT 2.9
Amp: Conrad Johnson MF 2250 (solid state)
Pre-amp: Audio Electronic Supply AE-3 (next on the upgrade path, but will probably stay with tubes)
CD player: An ancient Phillips (1990) that works great, thank you (but also next on the upgrade path even though I compared it in January 2003 in my system to a new Audio Refinement CD Complete and a new Adcom GCD-750, and preferred the Philips in both cases!)
Turntable: Rega Planar 2 (circa 1987 - also on the upgrade path)

I listen to equal parts jazz (both electronic and acoustic) and classical (chamber and orchestral), with some pop thrown in.

I sure do appreciate your help, since my current cables are 3m long and only allow the speakers to be about 3 feet apart. Any questions, let me know. Again, thanks for sharing your time and thoughts!!

Rush