The balanced/XLR connection is great at noise rejection. If you are doing longer runs, balanced connections are the way to go. If you have very short runs from your processor to the amp, then you will be just fine with RCA (unbalanced) runs. Picking up noise on the cables depends on a number of factors including where you live.
From all the posts, it sounds like you're planning a big upgrade to your system.
From all the posts, it sounds like you're planning a big upgrade to your system.