In general, thicker gauge gives better and fuller bass, so don't look at cables smaller than 12ga, or you will probably be disappointed. And buy used, your budget will go a lot farther. If you are going to biwire for a net cost of $4-$6 a foot per side, or can stretch the budget a little, definitely go looking for a set of DH Labs Silver Sonic Q-10, internally biwired. You will not find anything better for less than ten times the price.