Used 6328's are hard to come by. Pro monitors easiest to acquire on the used market (ebay or craigslist) are Mackie HR624 and HR824.

A lot of savvy home theater owners use active studio monitors in the belief they are very good and constitute great value. They make a good decision, but are often not aware by what magnitude that is so. Performance parameters scientifically shown to most correlate with listener preference are primarily a flat amplitude response, varying by only a decibel or so, an off-axis response that is a close replica of the on-axis response, and which even at 75 degrees out exhibits only a gentle and controlled roll-off in the high frequencies, a fairly flat power response, and low distortion. Pitted against the $420 JBL LSR6325, your typical $10,000 high end consumer speaker will win in some areas, usually noise and distortion at high volume. But in the net tally, the diminutive JBL will humiliate it.
Indeed very few consumer speakers at any price can surpass a respectable active 2-way pro monitor, especially if paired with a room equalized subwoofer. Consumer speakers are all unacceptably colored. Revel Ultima's are one of the few that can compete with pro-monitors.
So it's not quite that pro-monitors are a good option. For most situations they are the ONLY choice that meet minimal standards of acceptable quality reproduction. Decent pro-monitors can be had for almost half the original cost of new ones. Given the speaker is overwhelmingly the dominant determinant of sound quality (the room being a significant second), a good condition used monitor is the best bargain in audio that can be had.

Agreed, you are preaching to the choir!