1script - 5:33 am on Dec 11, 2012 (gmt 0)

I have never personally seen GoogleBot crawl in alphabetical order, but I have seen it crawl in url-length order.

@deadsea: good catch! I forgot to mention that one! Also, a combined alphabetical AND URL length at the same time - downright creepy. Happens on forum sites all the time and easier to catch when it gets stuck on slight variations to some very popular topic that comes up over and over. I convert URLs into readable form, same as title but shortened to 60 symbols or less. Perhaps I get caught up in this alpha/length ranges because my URLs are less diverse in size than normal 'cause I cut down all long ones to exactly 60 chars.
Anyway, didn't want to hijack the thread, just to say that both types of crawl are possible and can combine with one another at the same time. And neither seems to have anything to do with rankings, real or PR.