Whenever I look at the users page, I expect the top row to be the highest rep users and so on down the line. It looks strange to me that it is sorted into columns instead. Anyone else think so?
What is really needed, if anything, is a visual separator to lead a user's eye in the right direction (vertically or horizontally).
It would be no better to sort horizontally than vertically. I'm not saying that vertically is better either.
This does seem a trivial issue though, and changing it after 2 years would confuse more people than it helped.
Don't change it!
Its taken me ages to make sure I have just enough, but not too much, rep to fool you into thinking I'm just behind hobodave.