I actually saw a link to this over on Discourse, but 64-bit is finally going to be the default choice when downloading the 13.10 iso. See the mailing list post here.

I say it's about time, in defense of 32-bit systems, I have an ancient Apple G3, that won't run Ubuntu anyway, but it does run Debian stable 32-bit without a gui very well. I installed the system about 3 years ago, and it just plain runs without any problems, it's so reliable, I rarely even remember to do updates.