Well, lemme throw in my .02.
Although I don't have many karma points (+16/-4 and I've never witnessed anybody -1 me after the points systems change. The -4 was given to me by default), I personally don't see the point of it.
There are those very few posts where I don't wish to waste space just to post "agreed" so I use the karma, because that was how great the post was, but what I notice a lot goes back to what Kimberly said: they are used as tools to judge people. For that reason, I would actually agree with HAL and wish for the removal of the karma system altogether. In a way, I see it as a distraction from the point of the posts to begin with.
I have very rarely seen an atheist +1 a theist here for their arguments despite disagreeing with them, and I have never witnessed in general, a theist not get butt hurt and just -1 everybody because they were offended.
In a way, it is a voting system, but in a way, it's a distraction. If one is a great poster, they don't need karma points to show it. If one is a crappy poster, you don't need -1s to get the message. They won't be around much anyways because our moderators step in, do their job, and moderate the problem at hand.
What matters is the posts, and not how we interpret them. Members like kcrady are the greatest posters this board has ever seen. A karma points system doesn't speak for him, his posts stand up on their own. The typical theists that come here and preach and troll, they don't need 5 billion -1s to know that they are causing trouble, their posts speak for them. With that being said, a theist dealing with karma points here is at a strong disadvantage because they are a minority member and not because they have necessarily bad arguments (and yes, we know 99.99% of them are bad). The only theist I've really seen respected here was Old Church Guy, and Magic Miles was starting to get something before I hadn't seen him again.
Overall, my feeling is the karma system is great for giving pats on the back, but I think anybody who would use the karma system to judge a post or a poster is a pretty shallow person, and probably needs to back away from the computer. Let the posts speak for themselves, not the karma points.