thumb up and down reviews
This (could) put the best reviews up top, but there could be tabbed versions of reviews (sort by date, thumbed up, thumbed-down, etc.)
Could be optioned as follows:
Amazon style: "This review helped me / This review doesn't help"
Forum style: "This review is funny / This review sucks"
I think what would be more helpful in this case would be the ability to comment on the reviews of others so that the comments would show up as a link from that page, or directly below the original comment.