The commenting/upvoting system stink over at /. The Reddit/HN style is so much better. They should have switched a while ago. It makes the site still feel like 1997.
Personally, I prefer the slashdot system. Limited voting points makes you think more carefully about spending them, and being able to differentiate between +1 Insightful and +1 Funny is nice too. Also, moving popular posts to the top is great for readers, but voters will then tend to upvote the already popular comments.
Agreed about the value of differentiating between different kinds of +/-1. Also Slashdot's meta-moderation is a significant advancement on its successors.
Disagree with the meta-moderation. It makes the site very echo-chambery, because people start modding up posts in line with the groupthink so that they will get meta-moderated positively.
Lack of a slashdot-like voting system is one of the reasons why, on reddit, subreddits become unreadable when they they hit a number of subscribers (e.g. 100k).