64 bit for me, my computer has 8 Gigs of ram so I didn't have any other option.
But I have had only a few compatibility problems, all have been resolved now.
I had to buy the latest version of Adobe Indesigh, and I had to get 3rd party software to run my scanner.
Epson seems to be really out of it when it comes to 64 bit drivers.
Kind of makes me mad since I was able to get software from someone else to run my Epson scanner, why can't they do it.