Not much of an expert here, but unless YOU really feel it is important to pay that much for cables you shouldn't. I used to run a computer shop and the generic cables we carried were every bit as good as the brand names, better in a couple cases, and our cost was less than $1 on all but the longest and most complex cables, which were still less than $5. We would retail those cables for anywhere from $5 up to as much as $60 for some SCSI ones, the markup was rediculous. I suspect that cables, be they computer or home theater, are for the most part when dealing with reputable sources, cables.
As for the SR7500, I just bought one 2 weeks ago and am very pleased with how it has opened up my speakers and music. It performs equally as well with movies and doesn't seem to break a sweat at the high levels I play it at. The only problem I have is a nitpick that the remote has to be set to amp to power off the unit.
Steve