I would guess that if this poll was posted today, after Win7's release, the numbers for 64-bit would be higher.
I haven't voted but at this time I use 32 bit Vista Home Premium dual booted with 32 bit Ubuntu 9.04. This weekend however I will be blatting the lappy and installing 64 bit 7 Ultimate and the current 64 bit version of OpenSuse
i used vista 32 bit and mint linux 8 32 bit and fedora 64 i like both as trouble free i like 32 bit you dont need to do any thing not a single tweak required but on 64 bit fedora i need to done some tweaking but as performance vice i see 64 bit rocks.....yea i agree few years back we cant see the much difference between 32 bit and 64 bit now now its clearly seen even if you run both live cd's you see the difference..... now in short why 64 bit i love use fedora 64 bit 6-8 hours daily and i use vista and mint linux occasionally may be once in 15 days to month and i get too lazy to tweak them as well thats why choose as them 32 bit for them .... one more reason for 64 bit i got 6 gb ram which utilised nicely in fedora 64 bit without using kernel pae
32-bit, software makers still make mainly x86 software and I don't like the 2 Program Files and duplicate apps of x64 Win.